Suspension questions for 69 camaro

[diesel25lrs]

This is based off a PM I sent Ron regarding my specific problems after reading another thread he posted on ("Let's talk anti-roll bars"). He asked me to start a new thread so that everyone can enjoy!

Ron,
Your article with Matt got me back out in the garage to do some measurements on my tire/track width...I just got in last week from a long Military deployment and am itching to get back onto "fixing" things so I have a couple questions for you if you don't mind...

Specs-69 Camaro with supercharged LS3-650 RWHP and 6spd T56. Speed Tech 3 link Torque arm complete setup-frame and all. QA1 springs/shocks-I'll have to look for the #s on them...this is a very stiff car and possibly looking to switch to a better adjustable shock/spring combo down the road when I get to the fine tuning...

Like I told you before it started as a restomod and I really enjoy auto-x but that was an afterthought when setting the car up and I'm still really learning- a lot...I believe my biggest mistake was not getting the AFX spindles with my package, I stuck with stock and old school pack hubs...due to build cost. I know that I need tall spindles to get the caster. I'm running about 5.5 deg. now with -1.5 camber and don't think I can get much more with current setup which includes G mod. Are you familiar with the AFX spindles and their specs? I have to change out my front brakes now to accommodate the sealed hubs...Are the C5/6 style spindles the only options for us to get greater amounts of Camber gain without using tall ball joints? You had mentioned getting up near 10deg of caster....

So I measured the tread width at F-69" /R-70", this was outside lip of tire on the pavement
Track width- 58.5" F & 57" R with a 10.5"W (275x19)front tire & a 13"W(345x20) rear.

Same as Matt, I also have been looking to go with a 315 or 335 front tire but from the track width issue you mentioned of keeping it at 1" difference, I'm not sure I can do this?

Also, I'm having my friend put a full chromoly roll cage in the car right now as well, hard to adjust suspension when the car is flexing differently every time... I had previously put the car on the scales and she is a little nose heavy at 55/45% F/R with only the 2 front bucket seats in. Hopefully by the time I get to fine tuning the suspension- the majority of the cage in the rear, the stereo and rear interior will shift some of that weight to the rear. I'm at 3200lbs now and should be at 3500 when all said and done.

I think another area I need to look at is ride height? the car is very low and headers/oil pan are about 3.5" off the ground. stance looks great and I had raised up a little due to tire rubbing. I do drive this car on the street a lot and worry about speed bumps and such...

Thanks,
Josh

[Ron Sutton]

Hi Josh,


Ron,

Your article with Matt got me back out in the garage to do some measurements on my tire/track width...I just got in last week from a long Military deployment and am itching to get back onto "fixing" things so I have a couple questions for you if you don't mind...
Thanks for your Military Service. You have my utmost respect & appreciation.

Specs-69 Camaro with supercharged LS3-650 RWHP and 6spd Tremec.
Cool !

Speed Tech 3 link Torque arm complete setup-frame and all.
Good choices.

QA1 springs/shocks-I'll have to look for the #s on them...this is a very stiff car and possibly looking to switch to a better adjustable shock/spring combo down the road when I get to the fine tuning...
I'm not a fan of this shock for your application.

Like I told you before it started as a restomod and I really enjoy auto-x but that was an afterthought when setting the car up and I'm still really learning- a lot...I believe my biggest mistake was not getting the AFX spindles with my package, I stuck with stock and old school pack hubs...due to build cost.
Nothing wrong with traditional bearing hubs, but the AFX spindle would be a major improvement. The C6 hubs & Bearing are good too.

I know that I need tall spindles to get the camber.
Hmmm. This is not the only way.

I'm running about 5.5 deg. now with -1.5 caster
I think you mean to say you're running +5.5 degrees of caster & -1.5 camber. Correct ?

and don't think I can get much more with current setup which includes G mod.
Hmmm. Do your Upper A-arms have slugs to move back more?
Is there more room to achieve caster with the shims?
What about changing the lower A-arms?
Can you cut the upper mount & move it back?
Can you get custom made A-arms?

(I'm just testing how serious you are about achieving the optimum geometry because it might not be a bolt-on solution.) :)

Are you familiar with the AFX spindles and their specs?
I'm familiar ... but not firsthand ... and I do not know the specs. If it is a copy of the C6 spindle, it has 9.15 degrees KPI/SAI.

I was also looking at the CPP version which are knock off steel models instead of the aluminum and much cheaper. I'm not sure if they are both directly designed off the C6 vette spindle or not?
I have heard they are, but I don’t have firsthand experience with either. I think the CPP versions are cast iron or steel (heavy) … adding to your upsprung weight … and therefore not what I’d recommend for serious AutoX competition. (But probably ok for everyday performance driving on the street.)

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either way, I have to change out my front brakes now to accommodate the sealed hubs...Are the C6 style spindles the only options for us to get greater amounts of Camber gain?
There are a lot of options, including custom spindles, which cost less than most folks think. One BIG question in this equation though is Scrub Radius. For optimum AutoX performance. Scrub Radius is important. The smaller the better … down to zero … and KPI/SAI plays a big role in this. The following diagram shows how Scrub Radius is calculated.


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The first goal with Scrub Radius … if possible … is reducing it, so the tire is not having to torque itself around a big radius when you turn the wheel. If that is not possible … the 2nd goal would be … at least not making it bigger. Caster, KPI/SAI, wheel back spacing & Scrub Radius … all need to be worked out together. You should not arbitrarily pick a spec for any one of these things without considering how they affect each other.

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I have a step-by-step process I follow ... with the goal being optimizing the contact patch of both tires, while turning hard on tight corners of AutoX tracks or Road Courses .

A. I have to work out the Spindle KPI/SAI with the length of the A-arms, tire width & wheel backspacing ... to end up with a desirable scrub radius.

When I’m working out a car for class rules, those rules often limit what you can do for spindles & wheels. In more unlimited series there are less rules. On the street, there are no rules, except the ones you impose based on your desires, budget & priorities.

If I have a scenario where we are running front wheels with a lot of backspacing … that gets the KPI/SAI closer to the center of the tire … reducing Scrub Radius. “Zero Scrub” is optimum, but challenging to achieve for packaging reasons. It requires very wide wheels & deep backspacing. You can go too far ... with REALLY DEEP back spaced wheels & HIGH KPI/SAI spindles … you can get into a situation of negative Scrub Radius, which isn’t desired.

I recently designed a front end with 12” wide wheels & 10” of backspacing. A 8-10 degree KPI/SAI spindle would have put it into negative Scrub Radius. The spindle design & hub design also play a part on the packaging with the distance from the steering axis to the wheel hub face. With the hub we used & a 5 degree spindle, it created a zero scrub radius package.

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B. Once I know the spindle KPI/SAI, that guides me on how much “static” caster I need to build in to achieve a KPI/Caster Split favoring the caster.

Optimally, we need the 1.0-2.0 degrees more caster than KPI/SAI angle. A lot of Ford passenger cars run 8.0 KPI, so we’re shooting for 9.0+. A lot of GM spindles are 8.75 KPI, so we’re shooting for 10.0 +/-. If we can run a lower KPI/SAI spindle … like in the example above using a 5 degree KPI spindle … we’ll need 6.0+ degrees of caster.

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C. I need to work out if we want caster gain, or for the caster to stay the same, as the front suspension compresses fully under braking & turning (Term = "Dive") Think of this as “dynamic” caster, because it only happens when the suspension is compressed.

Quick Primer: When the front suspension compresses, if the angles of the lower control arm cause the lower Ball Joint to move forward and/or the angles of the upper control arm cause the upper Ball Joint to move back … that creates camber GAIN … in dive (compression). When the front suspension compresses, if the angles of the lower control arm cause the lower Ball Joint to move back and/or the angles of the upper control arm cause the upper Ball Joint to move forward … that creates camber LOSS … in dive (compression). We never want loss. When the front suspension compresses, if the angles of the lower control arm and/or upper control arm combine for no change in the ball joint locations … that is considered Caster Neutral. *Ask if you want the “how” explained more in-depth.

If we can get all the “static” caster we need, we will typically run only a small amount of caster gain. If we can’t get enough static caster, we need to build in more of caster gain to help us get to the desired total number.

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D. If I can get the caster I want ... statically and/or with gain ... so the KPI/Caster Split favors the caster 1.0+ ... I can run less Camber, which is the goal. We're always going to run SOME static camber (negative) … say –0.5 at a MINIMUM … and we always want SOME Camber gain … but if we don’t end up with a KPI/Caster Split favoring the Caster by 1.0+ degrees … then we need to make the difference with Static Camber & Camber Gain.

This is NOT ideal, because Camber by itself helps the angle of the outer tire achieve optimum contact patch … and hurts the angle of the inner tire, preventing optimum contact patch. The more static camber & dynamic camber we have to run … to make the outer tire work best … the more it hurts the contact patch of the inner tire.

If we can get to the optimum angle with a KPI/Caster split favoring the caster by 1.0+ degrees … either statically or in dive … we will run smaller amounts of static camber & camber gain. This is optimum. But if we don’t … we’ll run all the camber we need to … to make that outer tire WORK.

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E. Once I know how much camber I need for that combo, I work out how much of it is going to be static camber & how much is going to be camber gain.

We always want some static camber. -0.5 is like the minimum. I like -1.0 to -2.0 … IF everything above falls into place.

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F. How we get the camber gain, & how much, affects the car's static & dynamic roll center ... so they have to work as a team too.

Our desired roll center plays a role in this decision, because all the A-Arm angles creating Instant Centers determines where the static Roll Center is ... and where it goes dynamically in dive.

It should be clear now why I don't start with Camber.

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All of this ... is to optimize both front tire's contact patch with the asphalt ... In the car's dynamic states when it's driven HARD ... meaning turning, braking, rolling, unwinding & accelerating to the limits of the car, tires & driver ... sometimes beyond.

I realize this is a lot to digest. Don’t be afraid to ask questions where ever I wasn’t clear. [/B]


You had mentioned getting up near 10deg....
Yes … 10+ degrees of caster with the C6 spindle, since it has 9.15 degrees of KPI. The KPI/Caster split is usually in its happy window with 1.0-1.5 degrees more caster than KPI for tight cornering.

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So I measured the tread width at F-69" /R-70", this was outside lip of tire on the pavement
Track width- 58.5" F & 57" R with a 10.5"W (275x19)front tire & a 13"W(345x20) rear.

Same as Matt, I also have been looking to go with a 315 or 335 front tire but from the track width issue you mentioned of keeping it at 1", I'm not sure I can do this?
Like I’ve mentioned before … that 275/345 is going to look bitchin’ … but it’s not going to handle great … especially in a car with 55/45 F/R weight balance. My advice would be to get the widest tire you get in the front … and then put rear tires on it to match … for competing.

The car I’m building will run 285’s in front & 355’s in rear for cruising & car shows, but when I track it, which will be often, it will have 335’s all the way around. But this requires a 2nd set of wheels. If you can afford it, I’d suggest something like that.

As far as front track width … if you go to wider tires … and can make them work with deeperback spacing … thereby adding the tread on the inside … and still have adequate turning radius to compete … the front track width will narrow closer to matching the rear track width* … which is a good thing … AND … the scrub radius will shrink.

*I’ll expand on [/B]tuning with track widths[/B] if you want.

Thanks much for your advice!
Josh

No worries. Enjoy helping.

[diesel25lrs]

Ron,
I had made a couple changes to the original email I had sent you for this post...I caught my Caster/Camber switch...hahaa... Also after doing some more research on the spindle after the email-the ATS C5/6 is what I'll be going with for my application.
Going down the line to answer your questions-

Shocks/springs- That is what came with my package so I'm open to whatever later on down the road. My goal is to fix the big items first that will help the most and get to the shocks/springs once I have the car cage and interior in-for weight reasons. The QA1s aren't really hurting me right now while I have much bigger issues..

A-arms- I'm running the Speed Tech upper and lowers and I believe the way the made them and where they put the mounting bracket is probably optimum to run with their tall spindle to get that 10deg caster...The upper mounting bracket has the Guldstrand mod cut into it and I currently have the arms pushed all the way back and shimmed out as much as I could get it. I ran into problems with the a-arm hitting the shock while not loaded so I think I'm getting about all I can at this point with the stock spindle... By slugs I'm guessing you mean an adjusting nut on the a-arm itself like some others I've seen? but no, these don't have them.

ATS spindles- Tall spindle improves negative camber gain under suspension load
-Super light weight 2.9lbs.
-1.4" taller for improved camber curves and roll center with minimal tire wear
- Forged from ultra lightweight, exceptionally strong 7075 T73 (Tall)6061 T6 (Standard)aluminum
- Uses sealed C5 Corvette hub assembly with integrated wheel speed sensors
- Revised bolt-on steering arm location improves bump steer
- Direct bolt-on spindle replacement for A-F-X body vehicles
- One inch ride height drop for lowered look

I'm understanding your explanation of static and dynamic caster above- easy to measure and setup static but how do I-"joe blow" in the garage measure for dynamic without an expensive machine. Ie- how do I compress my wheel to simulate dive and check to see that I get near zero loss and remain neutral?

Tires and Front track width- It appears that I'm 1.5" + on the front vs. the rear already...Without buying new wheels for backspacing, I can go in .25" right now due to a spacer. The other main issue is rubbing on the inner fender well/frame. I will have to do some measurements to see how much more I can actually go before hitting either lock to lock. I do have some built in stops but would lose turn radius... I would be willing to do some inner fender well mods but not much I can do on the frame...It is much easier to go 1-1.25" outside with a wider tire by switching out fenders.
So with that said- If I do increase my track width in the front by 1" on each side for a total of 2", that would put me about 3" wider track in the front if I take out the .25" spacer on both sides for more backspacing... What will 3" more in the front do to my handling, am I just causing more problems?

[Ron Sutton]

Hi Josh,


Ron,
I had made a couple changes to the original email I had sent you for this post...I caught my Caster/Camber switch...hahaa... Also after doing some more research on the spindle after the email-the ATS C5/6 is what I'll be going with for my application.
Good call.

Going down the line to answer your questions-

Shocks/springs- That is what came with my package so I'm open to whatever later on down the road. My goal is to fix the big items first that will help the most and get to the shocks/springs once I have the car cage and interior in-for weight reasons. The QA1s aren't really hurting me right now while I have much bigger issues..
No worries.

A-arms- I'm running the Speed Tech upper and lowers and I believe the way the made them and where they put the mounting bracket is probably optimum to run with their tall spindle to get that 10deg caster...
Sounds good.

The upper mounting bracket has the Guldstrand mod cut into it
Great

and I currently have the arms pushed all the way back and shimmed out as much as I could get it. I ran into problems with the a-arm hitting the shock while not loaded so I think I'm getting about all I can at this point with the stock spindle...
Make sure at ride height you end up with a minimum 1/8"-3/16" clearance between A-arm & spring so it doesn't rub during suspension travel. Put some masking tape on the A-arm where it "might" ... test run it a bit & check ... run it hard & check again. Any rub ... and you need to move it.

Just for giggles ... post some photos we can see

By slugs I'm guessing you mean an adjusting nut on the a-arm itself like some others I've seen? but no, these don't have them.
Yes, that's what I meant, but it doesn't matter, because it sounds like you're close to the spring anyway.


ATS spindles- Tall spindle improves negative camber gain under suspension load
-Super light weight 2.9lbs.
-1.4" taller for improved camber curves and roll center with minimal tire wear
- Forged from ultra lightweight, exceptionally strong 7075 T73 (Tall)6061 T6 (Standard)aluminum
- Uses sealed C5 Corvette hub assembly with integrated wheel speed sensors
- Revised bolt-on steering arm location improves bump steer
- Direct bolt-on spindle replacement for A-F-X body vehicles
- One inch ride height drop for lowered look

I'm understanding your explanation of static and dynamic caster above- easy to measure and setup static but how do I-"joe blow" in the garage measure for dynamic without an expensive machine. Ie- how do I compress my wheel to simulate dive and check to see that I get near zero loss and remain neutral?
Well Joe ... wait, I thought you were Josh.

As you know, I input all the data into a suspension program. But years ago, I would simply pull the spring out & run the A-arm/spindle assembly through it's travel.

2 ways to check caster gain/loss:

1. Some spindles have a flat spot on the upright where you can solidly place a digital angle gauge. Take a reading at ride height. Then compress the suspension 2" ** & take another reading.

2. Using a caster gauge that attaches to the spindle ($99 - see photo) ... take a reading at ride height. Then compress the suspension 2" ** & take another reading.

** I said compress it 2" to keep it simple. But we like to know exactly what our suspension is going to travel and compress the suspension exactly that amount, so we get a total net caster change. With experience, you'll get to this point too.



78050


Tires and Front track width- It appears that I'm 1.5" + on the front vs. the rear already...Without buying new wheels for backspacing, I can go in .25" right now due to a spacer.
If you're saying your front track width is 1.5" wider than the rear track width is ... I'd work on reducing that. 1" wider with the front track with is about the max I go. Too much wider than that & you have a hard time getting the push out of it.

Are you saying you move the front wheels in .25" total ... or .25" each for a total reduction of .5" ?

The other main issue is rubbing on the inner fender well/frame. I will have to do some measurements to see how much more I can actually go before hitting either lock to lock. I do have some built in stops but would lose turn radius... I would be willing to do some inner fender well mods but not much I can do on the frame...It is much easier to go 1-1.25" outside with a wider tire by switching out fenders.
This is a personal preference. But for my car I'm going to give up a little turning radius ... not much, just a little ... to optimize track driving performance.

This can lead to a funny dilemma. When you AutoX it ... if you run it too wide ... so you keep your turning radius ... and the front end pushes ... you will end up using that turning radius trying to avoid cones & walls. On the other hand ... if you run it a bit narrower ... and the front end doesn't push ... you won't need the additional turning radius on track. Just tight parking situations.

So with that said- If I do increase my track width in the front by 1" on each side for a total of 2", that would put me about 3" wider track in the front if I take out the .25" spacer on both sides for more backspacing... What will 3" more in the front do to my handling, am I just causing more problems?
Problems that you, I & 10 Rocket scientists could not cure ... and still keep the car fast anyway.

[Ron Sutton]

P.S. With the magnetic base, this Joe's unit (as well as other brands) will attach & stick to the brake rotor hub, if you remove the grease cap. That way you don't have to take the rotor & hub off.

[diesel25lrs]

Ron,

1st pic shows my spring just about rubbing on my UCA while hanging, obviously it doesn't do that with weight on it.
2nd pic shows inside wheel clearance of almost 1" from wheel to LCA and sway bar.
3rd is UCS clearance of almost 3 fingers or 2.5"...haha
4th is so you can see where I have my shock adjusted to which I think I need to raise the ride height a little
5th is pretty much fully compressed and I can't fit my pinky in between the coils

Are you saying you move the front wheels in .25" total ... or .25" each for a total reduction of .5" ?
.25" each side for a total of .5" by removing the wheel spacers

I re-measured the track width again and coming up with the same #s....1.5" wider in front the way I'm sitting now...so this tells me that I really can't go outwards with a wider tire by following the track width rule of 1".
As you can see from the photos, I don't have much room to go inward either...What do I do?
Can I notch and re-weld the LCA and sway bar giving myself possibly another 1-1.5" inward? There is plenty of frame clearance and meat on those bars...
I'm just trying to understand how I've seen 2 Camaros now running 305s on the front and smoking everyone on the track? They would have to have more than +1 track width running that?
I would be willing to move my stops out a bit as well to reduce radius- I guess I'm going to have to play with it and measure to see what I can fit...

Thanks,
Josh



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[Ron Sutton]

Hi Josh,

Ron,

1st pic shows my spring just about rubbing on my UCA while hanging, obviously it doesn't do that with weight on it.
You care about how close it is in partial droop, but not so much in full droop (extension), because it will only see full droop when it is jacked up. Where you really care is ride height & in dive ... and it will be going away from the coil spring, so you should gain clearance. If that is the case, then you "can" move the UCA back for more caster.


2nd pic shows inside wheel clearance of almost 1" from wheel to LCA and sway bar.
It is the same distance ... 1" ... from both the LCA & Sway Bar? I could not tell from the picture.

3rd is UCS clearance of almost 3 fingers or 2.5"...haha
Plenty

4th is so you can see where I have my shock adjusted to which I think I need to raise the ride height a little
Please clarify why you think you need to raise the ride height? I'm not suggesting anything one way or another ... just curious on the why?

5th is pretty much fully compressed and I can't fit my pinky in between the coils
Neither the shock nor the spring is stopping the suspension from compressing farther. What is?


Are you saying you move the front wheels in .25" total ... or .25" each for a total reduction of .5" ?
.25" each side for a total of .5" by removing the wheel spacers
OK. Got it.

I re-measured the track width again and coming up with the same #s....1.5" wider in front the way I'm sitting now...so this tells me that I really can't go outwards with a wider tire by following the track width rule of 1".
Well ... you "can" do anything you want (LOL) ... but the front-to-rear track width (not tread width) relationship plays a BIG role in how the car handles.

If you have a car where the front-to-rear track width relationship is equal ... and narrower the front track width from there ... that will load the front tires more, making the car turn better to a point). Too narrow & it will get loose on entry. If you widen the front track width past the rear track width ... that will load the rear tires more, making the car tighter. Too much & it will push on corner entry & middle.

I like the front to be a little wider ... 1/2" to 1". More than that ... and the cars rolls too unevenly ... onto the outside rear tire ... and off the inside front tire = push!

We can work easily with a 1" wider TW in the front. But if you get the front 3" wider, you'll need a very high travel front suspension and/or some pretty serious band aids to get it to turn well. Your goal ... if I understand correctly ... is to get the car to turn better & carry more cornering speed. Making the front & rear tire width matching is a good move, but not by widening the track width to a 3" difference.



As you can see from the photos, I don't have much room to go inward either...What do I do?
I can't tell you what to do. It's your car & your decision. I can tell you what effect changes will have & you can decide what you want. Which is all that matters.

I will say, if you can get wider front tires on the car & keep the front-to-rear track width relationship within bounds it is going to turn better & carry more cornering speed. But to go wider & keep the front-to-rear track width relationship within bounds you need to either ...
a. Do so with deeper backspace wheels, make as clearance as possible & be ok with a reduced turning radius.
b. Widen the rear track width.
c. Some balance of the two.

That is what I would do, but it's not my hot rod.



Can I notch and re-weld the LCA and sway bar giving myself possibly another 1-1.5" inward? There is plenty of frame clearance and meat on those bars...
I would not suggest that. If you go the wider tire/deeper backspace route ... and the turning radius is too limited ... I would consider a 3-piece splined sway bar assembly, tucked in tighter ... and a custom LCA with a little different design.

Look at what Mike Maier did on Brian Hobaugh's car. His build thread is on this site.


I'm just trying to understand how I've seen 2 Camaros now running 305s on the front and smoking everyone on the track? They would have to have more than +1 track width running that?
Unfortunately I don't know that. Can you ask them? Most PT guys are pretty open.

I do know a lot of them have done what I suggested above ... and some have widened the fenders front & rear. There are threads on this forum showing what they did to the fenders.

I would be willing to move my stops out a bit as well to reduce radius- I guess I'm going to have to play with it and measure to see what I can fit...
I agree. Let me know where you run into problems & if I can help.

Thanks,
Josh

[diesel25lrs]

P.S. With the magnetic base, this Joe's unit (as well as other brands) will attach & stick to the brake rotor hub, if you remove the grease cap. That way you don't have to take the rotor & hub off.

Thanks Ron,
I have been in the market for a good one! I have been borrowing a buds that is exactly like that one. Think. I'll pick up my own now!

Yes, LCA and sway bar appear to be in the same spot where it would potentially be the rub point with wider tires.

I'm wanting to raise the ride height about 1" due to the fact that my headers and oil pan are currently only about 3" off the ground. I have only bottomed out once on a big dip on a country road but speed bumps/RR tracks have not been an issue yet...

Ok- So I had to go back and compress the shock again to see why the whole car is lifting off the jackstand without the shock or spring being compressed...It has to be the sway bar stopping it from compressing more as there is definitely more wheel well and shock to go.

I found out one guy running 305s on the front is a 68 and he didn't have the track width issues I do...he was originally running 325 R & 275 F tires and was -2.5" on the front TW so he needed to go outwards to fix his...not the case with mine...I'm curious if my aftermarket subframe is different than stock...I will have to check on that. I can't touch the rear without doing some fender flares and spacing out my wheels-not going there...only fix I can see is to get some more tire inwards on the front...

Brainstorming here and this is what I came up with- after your recommendation of a custom LCA...apologize for it being sideways but you get the idea. Do you see any strength issues with this sort of design other than aerodynamics?
78099

The sway bar will have to be changed as well...looking into the 3 spline that you mentioned.

Thanks,
Josh

[diesel25lrs]

Would it be a correct assumption to make that my front sway bar is too stiff to allow the front shocks/springs to fully compress & work properly or am i missing something else?

[Ron Sutton]

Hi Josh,

Thanks Ron,
I have been in the market for a good one! I have been borrowing a buds that is exactly like that one. Think. I'll pick up my own now!
There are lots of brands. The Joe's Racing version is nice & cost less than most ... around $100.


Yes, LCA and sway bar appear to be in the same spot where it would potentially be the rub point with wider tires.
OK, so you know if you're going to move one, you'll need to move both. I do want to suggest you look at how much the steering radius would be reduced ... before making these changes ... as I do NOT know ... but it may be something you can live with ... and maybe not.

I'm wanting to raise the ride height about 1" due to the fact that my headers and oil pan are currently only about 3" off the ground. I have only bottomed out once on a big dip on a country road but speed bumps/RR tracks have not been an issue yet...
Does the oil pan stick down below the cross member?

Does the oil pan have road rash on it?

Which sticks down lowest ... headers or oil pan?

At it's current height ... how far is the frame clip from the ground?


Ok- So I had to go back and compress the shock again to see why the whole car is lifting off the jackstand without the shock or spring being compressed...It has to be the sway bar stopping it from compressing more as there is definitely more wheel well and shock to go.
Yup. Probably. Just unhook one side for this test. We just want to confirm what is stopping travel first ... shock (bad), spring (bad) or an A-arm bumpstop, chassis bind, etc?

I found out one guy running 305s on the front is a 68 and he didn't have the track width issues I do...he was originally running 325 R & 275 F tires and was -2.5" on the front TW so he needed to go outwards to fix his...not the case with mine...I'm curious if my aftermarket subframe is different than stock...I will have to check on that. I can't touch the rear without doing some fender flares and spacing out my wheels-not going there...only fix I can see is to get some more tire inwards on the front...
I'm having a difficult time comprehending how his can be so different? Hopefully someone will chime in on this thread & shed some light on this with first hand experience.

Brainstorming here and this is what I came up with- after your recommendation of a custom LCA...apologize for it being sideways but you get the idea. Do you see any strength issues with this sort of design other than aerodynamics?
You're on the right track, but I would not make the "S" as pronounced as you have drawn it. Something similar to how Speedtech shapes their UCA's makes sense, or a simpler triangle design like the one I pictured here.

78251

The sway bar will have to be changed as well...looking into the 3 spline that you mentioned.
For your goals, you're going to want something in the 500-800# effective rate range. You won't know exactly what works best for your application until you get it all the together. A good thing with the 3-piece splined bars, is if you need a different rate, you just swap out a bar.


Thanks,
Josh[/QUOTE]

[Ron Sutton]

Would it be a correct assumption to make that my front sway bar is too stiff to allow the front shocks/springs to fully compress & work properly or am i missing something else?

If you mean by jacking 1 corner ... then yes. Unbolt one end of the sway bar.

[GeoffP]

Subscribed - curious to see where this goes from here!

[Ron Sutton]

Thanks for joining us Jeff. Chime in if you want.

[diesel25lrs]

Hi Ron,

Geoff, Hope to see you at RTTH again this year!

So I spent the day measuring and looking over things again. I made a mock up of a simulated wider inner front rim by 1.5" to rotate and check clearances and make sure I'm not wasting time with this idea... Appears my eyeball is correct- forward side of LCA and sway bar are the problem areas and everything else looks good.
I also did some research on other cars running the wider front tires to see what they did. Blu Balz had the rear quarters and fenders widened, giving him an overall wider TW. OLC is running 305's all the way around and just widened the front fenders to match up his TW. Larry Woo's Camaro build said they just massaged the inner fenders....all 68 Camaros, haven't seen a 69 done without TA style flares as of yet...

I spoke with Blake at Speed Tech and my frame is the same width as stock but he mentioned the reason I probably have such a wide front TW is due to the hats on my brakes...So I pulled the tires and measured them...2" wide each side. I believe the C5 hub that I will be putting on soon with my tall spindles only has a 1.25" offset. That will move me inwards .75" minus the .25" for my wheel spacer= 1" inwards each side just by changing out my brakes and hubs.

I researched online the 3 piece splines sway bar here- http://www.schroedersteering.com/ArmsPg.html and also at speedway. I'm not exactly sure how or where these arms would attach vs. the Hellwig I'm running now?
7828978291782927829378294

As you can see in the 1st pic, I have about 2" overlap of the sway bar past the frame on each side. I could possible shorten up the overall length of the bar, tucking it tighter to the frame. The second pic shows a part of the bar that could be lengthened by about 2" to move the "arm" of the bar back towards the shock more and give me the needed clearance which is available in pic 4. The whole reason for going with a custom LCA and sway would be so that I wouldn't lose the any turning radius. I agree Ron, something like the shape of the ST UCA should work on the bottom. I think I can pretty easily remove the forward bar and weld in a custom shaped bar, re-using the current LCA.

I unhooked the sway bar to test out the shock and I got a little more out of the shock compression but not much before it lifted the car off the stand. I was able to push down on the fender and get more movement out of the shock with sway bar off vs. on...but not much movement either way...

The headers are the lowest part under my car but not beating the oil pan by much...The one big dip I hit just ripped off the header wrap in the spot by the collector. So I'm thinking that .5" higher will suffice with the current shocks I'm running now. The oil pan has no road rash but sits about .5" lower than cross member in front of it...

My next step will be to get the new spindles, brakes and hubs on to see exactly what this changes before I make any big moves. Hoping to have this done in the next couple weeks!

[diesel25lrs]

The first goal with Scrub Radius … if possible … is reducing it, so the tire is not having to torque itself around a big radius when you turn the wheel. If that is not possible … the 2nd goal would be … at least not making it bigger. Caster, KPI/SAI, wheel back spacing & Scrub Radius … all need to be worked out together. You should not arbitrarily pick a spec for any one of these things without considering how they affect each other.

------------------------------------------------------------------------------------------------------------------------------------------

I have a step-by-step process I follow ... with the goal being optimizing the contact patch of both tires, while turning hard on tight corners of AutoX tracks or Road Courses .

A. I have to work out the Spindle KPI/SAI with the length of the A-arms, tire width & wheel backspacing ... to end up with a desirable scrub radius.

When I’m working out a car for class rules, those rules often limit what you can do for spindles & wheels. In more unlimited series there are less rules. On the street, there are no rules, except the ones you impose based on your desires, budget & priorities.

If I have a scenario where we are running front wheels with a lot of backspacing … that gets the KPI/SAI closer to the center of the tire … reducing Scrub Radius. “Zero Scrub” is optimum, but challenging to achieve for packaging reasons. It requires very wide wheels & deep backspacing. You can go too far ... with REALLY DEEP back spaced wheels & HIGH KPI/SAI spindles … you can get into a situation of negative Scrub Radius, which isn’t desired.

I recently designed a front end with 12” wide wheels & 10” of backspacing. A 8-10 degree KPI/SAI spindle would have put it into negative Scrub Radius. The spindle design & hub design also play a part on the packaging with the distance from the steering axis to the wheel hub face. With the hub we used & a 5 degree spindle, it created a zero scrub radius package.

------------------------------------------------------------------------------------------------------------------------------------------

B. Once I know the spindle KPI/SAI, that guides me on how much “static” caster I need to build in to achieve a KPI/Caster Split favoring the caster.

Optimally, we need the 1.0-2.0 degrees more caster than KPI/SAI angle. A lot of Ford passenger cars run 8.0 KPI, so we’re shooting for 9.0+. A lot of GM spindles are 8.75 KPI, so we’re shooting for 10.0 +/-. If we can run a lower KPI/SAI spindle … like in the example above using a 5 degree KPI spindle … we’ll need 6.0+ degrees of caster.

Ron, How do I figure out my scrub radius with my current A arm length and figuring in the tall C5 spindles? I would also like to change the values to factor in the wider wheel-not changing the backspacing. Do you have a formula, worksheet, or chart you go by? I think this should be my first step in getting to that 0 scrub radius vs. trial and error!

[GeoffP]

I actually chased the same thing you're doing to a lesser degree with my latest mods. I went with a 275 on all 4 corners and found my car to be VERY well balanced after the changes. Because of this, I put a good deal of thought to my changes though I didn't get as technical with it as you are. One thing I notice that has not been mentioned is that the 69 has a bit more clearance than 67-68's do (I assume you already know this but wanted to be sure). I will not be surprised if you will be able to fit a 295 front tire just by changing to the AFX spindle and matching brakes. Also as part of this change, assuming you're staying with Wilwood, it might be worth checking with them to be sure there isn't a lower cost way to change brakes by changing the abutment brackets and center rotor hub. This could be a huge savings over buying a whole new brake kit. I think with the spindle/brake changes you're planning plus the sway bar changes you should be able to just squeeze a 305 under the front but it may still rub at full lock. I hope this helps somewhat though I suspect what I've shared is stuff you've already thought of!

[Ron Sutton]

Hi Josh,


Hi Ron,

Geoff, Hope to see you at RTTH again this year!

So I spent the day measuring and looking over things again. I made a mock up of a simulated wider inner front rim by 1.5" to rotate and check clearances and make sure I'm not wasting time with this idea... Appears my eyeball is correct- forward side of LCA and sway bar are the problem areas and everything else looks good.
So that narrows down what needs to be modified to make this work & sounds like you're on the right track.


I also did some research on other cars running the wider front tires to see what they did. Blu Balz had the rear quarters and fenders widened, giving him an overall wider TW. OLC is running 305's all the way around and just widened the front fenders to match up his TW. Larry Woo's Camaro build said they just massaged the inner fenders....all 68 Camaros, haven't seen a 69 done without TA style flares as of yet...
That makes sense.


I spoke with Blake at Speed Tech and my frame is the same width as stock but he mentioned the reason I probably have such a wide front TW is due to the hats on my brakes...So I pulled the tires and measured them...2" wide each side. I believe the C5 hub that I will be putting on soon with my tall spindles only has a 1.25" offset. That will move me inwards .75" minus the .25" for my wheel spacer= 1" inwards each side just by changing out my brakes and hubs.
So ... the hubs & hats you have now are wider than most ... moving your tires & track width out. Good to know.
And you're going to a set-up that is 2" narrower. Now you're cooking with gas. :)

I researched online the 3 piece splines sway bar here-and also at speedway. I'm not exactly sure how or where these arms would attach vs. the Hellwig I'm running now?
You can run straight arms & attach them to the LCA just outside the frame rail ... or you can have the arms bent (easy & common) to turn outward & connect to the LCA somewhere farther out. Either will work, but things to know:

a. You need to know your current sway bar motion ratio + bar rate ... and therefore your current effective bar rate.
b. You would need take into account the mounting point you decide on ... the motion ratio it creates ... so when you pick a new sway bar size & rate ... you end up with the effective rate you desire.
c. This is NOT hard, but it is important.
d. If you want to change the sway bar rate, now would be a good time.
e. I suggest you go with steel or chromoly arms & avoid the aluminum.
f. If you're going to bend the arms ... get them un-heat-treated ... bend them ... and have them heat treated.
g. I recommend Speedway. Tell Kenny Ron Sutton referred you.



As you can see in the 1st pic, I have about 2" overlap of the sway bar past the frame on each side. I could possible shorten up the overall length of the bar, tucking it tighter to the frame.
Yes.

The second pic shows a part of the bar that could be lengthened by about 2" to move the "arm" of the bar back towards the shock more and give me the needed clearance which is available in pic 4. The whole reason for going with a custom LCA and sway would be so that I wouldn't lose the any turning radius. I agree Ron, something like the shape of the ST UCA should work on the bottom. I think I can pretty easily remove the forward bar and weld in a custom shaped bar, re-using the current LCA.
If you have fab skills ... or connections that do ... this is easy to do ... and easy to get the bushing angles wrong too ... so do it with care. Make sure the bushing holes/tubes are perfectly parallel before & after welding. The ultimate test is bolting the LCA back in the car & being able to move the LCA freely up-&-down with 2 fingers. You want NO BIND.

I unhooked the sway bar to test out the shock and I got a little more out of the shock compression but not much before it lifted the car off the stand. I was able to push down on the fender and get more movement out of the shock with sway bar off vs. on...but not much movement either way...
OH ! I get it now.

You were trying to compress it just by jacking. That's the challenge for me helping long distance ... I can't see what is going on. (Remind me to tell you a story about helping a guy by phone to install a distributor some time.)

You don't need to jack it up any farther. We just needed to make sure the shock isn't bottoming out & the spring is not coil binding. With the corner jacked as far as it will go ... measure the shaft showing on the shock ... and measure the spring gaps for total spring travel left ... and measure how far until the LCA/frame bump stop touches ... and post those numbers.


The headers are the lowest part under my car but not beating the oil pan by much...The one big dip I hit just ripped off the header wrap in the spot by the collector. So I'm thinking that .5" higher will suffice with the current shocks I'm running now. The oil pan has no road rash but sits about .5" lower than cross member in front of it...
OK. Of course, you don't want to raise it more than you need to ... and you have to make the call as how much clearance you're comfortable with. I assume you're planning to raise the rear too to maintain rake ... but I don't know ... so share that info next time.


My next step will be to get the new spindles, brakes and hubs on to see exactly what this changes before I make any big moves. Hoping to have this done in the next couple weeks!

Sounds good. Keep us in the loop & ask questions anytime you need guidance.

[Ron Sutton]

Josh,


Ron, How do I figure out my scrub radius with my current A arm length and figuring in the tall C5 spindles? I would also like to change the values to factor in the wider wheel-not changing the backspacing. Do you have a formula, worksheet, or chart you go by? I think this should be my first step in getting to that 0 scrub radius vs. trial and error!

As you know, I measure everything & work it out in a suspension software. But for "Joe Blow" ... :) ... do this:


a. Determine the EXACT centerline height of your front spindle (Pick one ... left or right ... doesn't matter) ... with all 4 wheels & tires on the ground ... suspension loaded. It is going to be around 12-13". Let's say it is 12-3/4".

b. Remove that tire & wheel. Put a good, non-leaking jack under the the ball joint (or other secure point on the lower A-arm) & jack the spindle back to that exact same height ... in this example 12-3/4". (you are simulating ride height ... with 3 tires on the ground & a jack under one front corner.

c. Using a string, laser, straight edges or whatever works for you ... make a true line through the CENTERS of the upper & lower ball joints ... projecting onto the floor. Mark it. (I use blue 3M masking tape, so I'm not marking up my floor permanently.)

d. Ideally ... you want the mark on the shop floor to be more than a dot. What works best is a line 8-12" long TRULY PARALLEL with the car.

e. Put your tire & wheel back on ... and set the car on the ground.

f. Find the true centerline of your tire tread ... and measure the distance to the line you put on the floor. Whatever that measurement is ... in inches ... is your scrub radius. This method may not be dead on accurate ... but it'll be close enough to know what you're working with.

78317

Please post the number, so I also know what we're working with.

[Ron Sutton]

Geoff,

Thanks for your input.

[diesel25lrs]

Geoff,
What is your F/R Track width? My biggest issue as you probably know is that I can't go outwards with my front wheels due to already being wider in the front with my 275s...Thanks for bringing that up- I wasn't sure if the 69 had more clearance or not than the 67-68...Good to know! I can fit a 295 with a 10" wheel now by losing a little bit of steering radius on the stops...I'm looking to go with a 305-315. I want to get the most out of this car that I can & I already need to make a few changes now...I already checked with Wilwood & Tobin at Kore3 and a couple other guys about reusing the brakes. basically the story is- I may be able to reuse the calipers but everything else has to go, rotor, hat, bracket(offset is different). So with that said- I will be better off selling my slightly used complete set and starting over. I think I'm going to try out Brakeman 4P tornado with a slightly smaller rotor, Warren sort of sold me after a long conversation over the phone...Plus they are much lighter of a setup so less rotating weight up front is a good thing. With just the spindle/brake changes I know I can get a 295 with a little steering loss, don't think a 305 will stuff under there without rubbing at full turn and a lot of steering loss...Though it depends on which 305 we are talking too, as we all know every brand of tire has different actual "mounted" widths...I'm looking to go with the pilot super sports which seem to run wider than most...For instance on my rears- I'm running a Nitto 345 which is the same mounted width as a PSS 325...


QUOTE=GeoffP;1002865]I actually chased the same thing you're doing to a lesser degree with my latest mods. I went with a 275 on all 4 corners and found my car to be VERY well balanced after the changes. Because of this, I put a good deal of thought to my changes though I didn't get as technical with it as you are. One thing I notice that has not been mentioned is that the 69 has a bit more clearance than 67-68's do (I assume you already know this but wanted to be sure). I will not be surprised if you will be able to fit a 295 front tire just by changing to the AFX spindle and matching brakes. Also as part of this change, assuming you're staying with Wilwood, it might be worth checking with them to be sure there isn't a lower cost way to change brakes by changing the abutment brackets and center rotor hub. This could be a huge savings over buying a whole new brake kit. I think with the spindle/brake changes you're planning plus the sway bar changes you should be able to just squeeze a 305 under the front but it may still rub at full lock. I hope this helps somewhat though I suspect what I've shared is stuff you've already thought of![/QUOTE]

[diesel25lrs]

Hi Ron,

I just got in from the garage doing some measurements and I'm awaiting a callback to find out exactly what the offset will be on my new brake/hub setup.

You can run straight arms & attach them to the LCA just outside the frame rail ... or you can have the arms bent (easy & common) to turn outward & connect to the LCA somewhere farther out. Either will work, but things to know:

a. You need to know your current sway bar motion ratio + bar rate ... and therefore your current effective bar rate.
b. You would need take into account the mounting point you decide on ... the motion ratio it creates ... so when you pick a new sway bar size & rate ... you end up with the effective rate you desire.
c. This is NOT hard, but it is important.
d. If you want to change the sway bar rate, now would be a good time.
e. I suggest you go with steel or chromoly arms & avoid the aluminum.
f. If you're going to bend the arms ... get them un-heat-treated ... bend them ... and have them heat treated.
g. I recommend Speedway. Tell Kenny Ron Sutton referred you.

ok- If I were to attach the arms to the inner edge of the LCA, about 5-6" inward from where it is now on the outer end of LCA, will that affect how it works and the movement of the LCA compared to how it is now? I'm guessing it will have to...

If you have fab skills ... or connections that do ... this is easy to do ... and easy to get the bushing angles wrong too ... so do it with care. Make sure the bushing holes/tubes are perfectly parallel before & after welding. The ultimate test is bolting the LCA back in the car & being able to move the LCA freely up-&-down with 2 fingers. You want NO BIND.

I understand what your saying here. my plan is to keep the LCA mounted after I cut the forward arm out- leaving the cutoff bushing in the mount and tacking it back together with the new designed tube piece in place, all while mounted up.

I got the scrub radius measurements pretty close I believe....
Current setup is 1.75" on the measurement from midline tire tread to tape.
I ran some simulated setups as well
Moving the wheel in 1" which I plan on doing next= .75" scrub
Moving wheel in 1.5"= .5" scrub... Will be very tight, even with my planned LCA/sway mods, so I will lose a hair bit of turn radius probably going in this far...
I'm also guessing that my tall spindle when put on will take these #s down even more?

I forgot to get the shock shaft measurement and coil gap. I will try to get those tonight and post the #s...I didn't see any coil bind though...

Thanks,
Josh

[Ron Sutton]

Hey Josh,

Hi Ron,
I just got in from the garage doing some measurements and I'm awaiting a callback to find out exactly what the offset will be on my new brake/hub setup.
Cool. Let me know the outcome when you get the info.

ok- If I were to attach the arms to the inner edge of the LCA, about 5-6" inward from where it is now on the outer end of LCA, will that affect how it works and the movement of the LCA compared to how it is now? I'm guessing it will have to...
It changes the sway bar "motion ratio" ... which is like a leverage ratio ... so you will need a stiffer sway bar ... to end up with the same "effective bar rate" you currently have. This is a good time to change sway bar rates if you want to.

I understand what your saying here. my plan is to keep the LCA mounted after I cut the forward arm out- leaving the cutoff bushing in the mount and tacking it back together with the new designed tube piece in place, all while mounted up.
OK. But that won't prevent it from "tweaking" during welding. Check it often during the welding process & redo it if it's tight. Do NOT settle for any degree of bind.


I got the scrub radius measurements pretty close I believe....
Current setup is 1.75" on the measurement from midline tire tread to tape.
About what I expected.

I ran some simulated setups as well
Moving the wheel in 1" which I plan on doing next= .75" scrub
That would be good.

Moving wheel in 1.5"= .5" scrub...
I think you mean it would end up as .25" scrub ... which would be awesome.

Will be very tight, even with my planned LCA/sway mods, so I will lose a hair bit of turn radius probably going in this far...
It's your car, so you have to deiced what your priorities are. The more you decide to move the new wider tires "in" ... the closer the front track width will be to the rear track width ... and the smaller & better your scrub radius will be. All good.

If you move the tires & wheels "IN" 1" ... what is the front track width ... and how much does that make it wider than the rear track width? How about at 1.5" "IN" ?

I'm also guessing that my tall spindle when put on will take these #s down even more?
That depends. The ATS has a larger KPI, so ... IF ... the spindle doesn't move the tire ... it will reduce the scrub radius some. Does that make sense?


I forgot to get the shock shaft measurement and coil gap. I will try to get those tonight and post the #s...I didn't see any coil bind though...

Thanks,
Josh

No worries. Post them when you get them.

[diesel25lrs]

Hi Ron,

Ok, I need to find out my current sway bar rate & go from there. I'll talk to Speedway & tell them what i'm doing & see what they recommend. We'll have to discuss this further when the time comes about how much sway bar # i need with the new shock setup.

Gotcha on the welding/warping/binding part...a friend is a master tig welder.

I remeasured the scrub for going in 1.5" which would bump me to about 11" overall. This actually gave me a -.5" scrub... I take it that negative is also bad...

Currently i'm at 58.5F/57R TW
Going in 1.5" x2= 3" on front would give me
55.5F/57R

Going in 1"x2=2" is 56.5F/57R

I will have to recheck everything when i get the new spindles/brakes on soon-Can't wait

[GeoffP]

Hey Josh,

Yes, there's a pretty good bit of difference in the 67-68 and the 69. You can really get an idea of the difference if you look at them side-by-side. The 69 is a good bit wider at the nose than the 67-68. If you can already fit a 295 without changes other than narrowing the turning radius then I suspect a 305-315 will fit great after your planned changes but I think you will have to sacrifice some turning radius to get a tire that big on the front. I lost some on my car by going from a 245 to a 275 but that's with a stock sub. The radius difference is really only noticeable when navigating parking lots. Otherwise I don't notice it at all - I don't know how much I'd worry about a minor reduction in turning radius to get the bigger tire to fit. Another thing to remember that you've already addressed is that your SpeedTech sub should offer some additional clearance especially if you change the sway bar. I'll go measure the track width right quick with a tape and let you know shortly.

[GeoffP]

Josh,

My track width measured from the outside edge of each wheel is:

Front 70"
Rear 70.25"

This is with 275/35-18" on 18x9.5 ET15 wheels. The brakes are Wilwood front and rear 12.19" rotors. The rear rotor slides over the axle hub and the front rotor bolts to the rear of the hub. The rear adds nearly 1/4" to the track width on each side whereas the front does not add anything. In my case, my front wheels would not fit if my rotors slid over the hub instead of bolting to the back of the hub. The wheels would rub the outer lip of the front fenders (they do under extreme compression or when I had the car lower than it is now).

[diesel25lrs]

Hi Ron,
Sorry- i had smoke coming out my ears measuring & thinking up different backspacing, tire/wheel combos to get different scrubs...

So yes- if i could move my wheel in 1.5"-scrub would be .25

In 1" is .75 scrub

If i move wheel in 1" & add a new +.5" lip to my inner wheel- gives me .5" scrub.
I believe i will only get 1" out of my current center for the backspacing with the new brake hub offset & losing the spacer.

Make sense now? You say we want to shoot for zero scrub- how much is forgivable in your experience on a race car- .25, .5, .75?

[diesel25lrs]

Thanks for the info Geoff! Not to knock on you but it sounds like you measured the tread width being at 70" instead of track. Track width is center of tire to center of tire or inside lip of one to outside lip of other will give you same numbers. Ron schooled me on that one... Ha
I also want to make sure i take everything into consideration this time around- caster,camber, scrub radius,bumpsteer, ackerman...etc.. Want it to be a nasty track car so i have no excuses but my lack of driving ability! Lol...

[Ron Sutton]

Hey Josh,

"Hi Ron,

Ok, I need to find out my current sway bar rate & go from there. I'll talk to Speedway & tell them what i'm doing & see what they recommend. We'll have to discuss this further when the time comes about how much sway bar # i need with the new shock setup.

Gotcha on the welding/warping/binding part...a friend is a master tig welder.
Excellent!

I remeasured the scrub for going in 1.5" which would bump me to about 11" overall. This actually gave me a -.5" scrub... I take it that negative is also bad...

Currently i'm at 58.5F/57R TW
Going in 1.5" x2= 3" on front would give me
55.5F/57R

Going in 1"x2=2" is 56.5F/57R

Whoa! That’s too far in.

Something has changed since we started discussing this. So help me get clear. Originally … you were looking at going 2” wider on front tires & wheels … and all of the additional 2” of tire was going to be added on the outside.

Then we discussed modifying your lower A-arms & sway bar to shift 1” to the inside … and the other 1” stays on the outside.

------------------------------------------------------------------------------------------------------------------------

I love math ... but when the numbers are spread out like a picnic, it can get confusing. So here is an outline of where I "think" we are.

Current Set-up:
Front: Tires 10.5"W (275x19) … Track width is 58.5" … with Scrub Radius of 1.75”
Rear: Tires 13"W (345x20) … Track width is 57”

You’re replacing the front tires with tires 2” wider. If you used wheels exactly 2” wider … with exactly 1” more backspacing than you currently have … you would keep the same tire centerline … same front track width … and same scrub radius. You would have 1” more tire on the inside & 1” more on the outside.

This was my original suggestion … but you said it wouldn’t fit. Then you found an inch if you modify you LCA & install a 3-piece sway bar. So it will fit.

But … now, you are talking about going in much farther ... like 1 to 1.5" on each side ... and that is:
1. Confusing me on “how “ you can make it fit.
2. Too far ... even if it is possible.
3. Unnecessary … as moving each tire centerline in ½” would be ideal for your application.

------------------------------------------------------------------------------------------------------------------------

My suggested Set-up:
Front: Tires 12.5"W (315x19) … track width is 57.5" … with Scrub Radius of 1.25”
Rear: Tires 13"W (345x20) … track width is 57”

Replacing the front tires with tires 2” wider … using wheels exactly 2” wider … with exactly 1.5” more backspacing than you currently have … moving the tires in .5” each … 1” overall … for a 1” narrower front track width of 57.5" … and slightly smaller scrub radius of 1.25” … until you account for the increased KPI of the ATS spindles.

Going from a spindle with 8.75 KPI to 9.15 KPI will reduce the scrub radius about .1” … so you’ll end up with a 1.15” scrub radius = Good.

------------------------------------------------------------------------------------------------------------------------

If I misunderstood anything, please correct me.


I will have to recheck everything when i get the new spindles/brakes on soon-Can't wait

Cool. Us too. We’re excited to see you get your hot rod back on the road & track with wider front tires, better camber gain & lower scrub radius.

[GeoffP]

Yep I read your numbers and figured I did it wrong. You can knock 9.6" off each side for true track width then. That's taking the measurement from the outside of the tire to the mount flange out of the figure times two to accommodate for the tire/wheel on each side. So if that's the case then it should be:

Front - 60.4"
Rear - 60.65"

My car has a OE rear axle that has not been narrowed if that helps and I'm running RideTech's full setup prior to their redesign on my car.

Edit - I got this value by plugging my wheel data into the calculator at this site: http://www.rimsntires.com/specs.jsp

[Ron Sutton]

Hey Guys,

I'm on the Forum today for a few more hours ... then I'll be gone for a week.


I'm meeting up with my friend Neil Porter at Sears Point where he's running 2 formula cars in SCCA racing.

https://www.pro-touring.com/attachment.php?attachmentid=78694&d=1373072350



Then I'm camping with my girls the rest of the week.

https://www.pro-touring.com/attachment.php?attachmentid=78695&d=1373072681



I'll be back online late Thursday (7/11) or Friday morning (7/18).

[diesel25lrs]

Hi Ron,

My suggested Set-up:
Front: Tires 12.5"W (315x19) … track width is 57.5" … with Scrub Radius of 1.25”
Rear: Tires 13"W (345x20) … track width is 57”

Replacing the front tires with tires 2” wider … using wheels exactly 2” wider … with exactly 1.5” more backspacing than you currently have … moving the tires in .5” each … 1” overall … for a 1” narrower front track width of 57.5" … and slightly smaller scrub radius of 1.25” … until you account for the increased KPI of the ATS spindles.

Going from a spindle with 8.75 KPI to 9.15 KPI will reduce the scrub radius about .1” … so you’ll end up with a 1.15” scrub radius = Good.

To do this I will have to change out to the the wider Anvil fenders. No room to go out any further on stock fenders. After the LCA/Sway mods, I should be able to move the current entire wheel in 1.25" comfortably, this will allow .25-.35" of "play" before getting close to anything else-frame... This will allow me to go back out 1.25" max to the outside lip to fender allowing me to run an 10.5" wheel. This will keep the current TW but reduce the scrub a little.

I'm seriously thinking about going full out Insanity at this point...
Here is what I'm thinking...
Stretch the rear quarters by 1.25" each side- bringing my rear TW out to 59.5

Anvil fenders will give me at least 1.25" outer clearance.
custom LCA/UCA/Sway setup to get the additional 1.25" inside clearance and to get the scrub down to near zero.
This will give me an additional 2.5" for a 12" rim and 325/13" tire! This will give me a new front TW of 59.75 almost matching the back as well as running same width tires on all four corners!
I need to enlist some help or find the software to model what length arms I need, as well as steering arm location for bump steer...That is a little over my head at this point but I'm willing to learn.
Anyone see any other issues I need to be concerned with up front?

[Ron Sutton]

I'm back form my trip.

When you get back from your trip ... let's pick up where we left off. I suspect having more time to think about this will have provided you some clarity on what you want to do and/or achieve.

I'm looking forward to helping you make it into the machine you want it to be.

[diesel25lrs]

Hi ron,

Still on my adventure but i just finished reading Herb Adams "chassis engineering" along with some of your other posts & it got me thinking...

1- seems a bit of my understeer issues could be cured by the addition of a rear sway bar to transfer some of the weight to the outside rear tire? On a torque arm setup- where would the mounting points for a rear SB be?
2- is there a good overall tunable setup for autoX & road racing? It seems that you can either run the SS/BB for short track/tight turns or the conventional stiff front/soft rear (which i would say i have now)... Can i tune to be good at both short & tight or long & fast without switching out springs & shocks or will it always be a compromise or happy medium/one or the other? It seems that the One Lap Camaro is doing it on both! I'm pretty sure that he won't give up his suspension tricks anytime soon...
The reason I ask is some of the courses are short & tight & some are longer & faster, & some include full on 100+mph sweepers. I would like to be able to quick change my setup if possible.

[Ron Sutton]

Hi Josh, as you learn stuff, I can tell there are some cloudy issues. I'll try to clarify things as best possible.


Hi Ron,

Still on my adventure
Enjoy your trip with your wife.

but i just finished reading Herb Adams "chassis engineering" along with some of your other posts & it got me thinking...
Cool.

1- seems a bit of my understeer issues could be cured by the addition of a rear sway bar to transfer some of the weight to the outside rear tire? On a torque arm setup- where would the mounting points for a rear SB be?
Uh ... that's not stated correctly ... at all. So I hope I didn't mislead people in one of my previous posts & apologize if I did. A rear sway bar will reduce the roll angle of car, primarily from the rear suspension of the car, but affecting the whole car. This achieves several things, one of which is ... with the outside rear suspension compressing less when cornering ... "staying up" in racer speak ... the cars rolls less diagonally ... and the inside front tire gets worked more.

As far as mounting points, I'm not a fan of trailing arm mounted sway bars. The best method is to mount/house the sway bar at the chassis & run the links to the rear end housing or mounts on the housing.

2- is there a good overall tunable setup for autoX & road racing?
Sure. There is a set-up that can do well at both. Not optimum at both, without some tuning, because a set-up to do well at low speed tight corners & high speed corners is going to be a compromise in between the two optimum set-ups.

But ALL suspension set-ups are a compromise to some degree. Even the most developed race suspension set-up running at Indy, Bristol, Laguna Seca & your local Autox track are compromises ... because they are not running in a perfect circle or straight line. Any time the track transitions from straights to corners, and corners to straights ... and of course when the corners are not the same ... the best teams have worked out the best compromise suspension set-up to perform the best.

It seems that you can either run the SS/BB for short track/tight turns or the conventional stiff front/soft rear (which i would say I have now)...
Again, there is cloudiness & I apologize if I caused it. I'll try to better clarify. First, the terms you're using are an over generalization, so I'd like to re-state them just so we're on the same page. Conventional stiff front/soft rear uses stiff front springs, but a soft sway bar, so during braking & cornering the front suspension does not compress much under braking & cornering, but the car rolls a lot. The modern suspensions are the other way around, where during braking & cornering the front suspensions compresses a lot, but does not roll much.

I suspect you may have mentally linked "conventional stiff front spring/small sway bar - low travel/high roll" set-ups with big track/high speed cornering performance ... and "modern soft front spring/big sway bar - high travel/low roll" set-ups with short track/tighter cornering performance ... but that's not accurate.

The two successful types of suspensions ... conventional stiff front spring/small sway bar - low travel/high roll ... and ... modern soft front spring/big sway bar - high travel/low roll ... have been used successfully at all types of tracks from AutoX to Laguna to Daytona. They are just different strategies to travel the suspension. The conventional relies on more roll, & the modern relies on more front suspension travel.

I used the term "have been used successfully" ... because the conventional strategy has NOT been used in the top levels of Indy, F1, Grand Am, NASCAR, ALMS, etc. for many, many years ... on any track ... big or small. At least not by any front running teams. They all are on the modern strategy of high travel/low roll angle.

Old school conventional strategies are still common in the lower ranks of racing in AutoX, grassroots road racing & short oval tracks. But the change is happening there too currently. I see it. There is a trickle down process of knowledge. Eventually a racer in each series tests & works out a modern suspension for their car ... and wins ... and slowly the evolution happens. As with any change, there is resistance by some people, and acceptance by others. This migration to the new strategy takes time ... years in fact. Again, I've seen it firsthand.

So to summarize, you can make either the conventional or modern set-up work on all types of tracks. If each suspension is well designed & tuned to its optimum, the modern set-up will have more front end grip in the middle of the corners, carrying more corner speed, providing a small, but important lap time advantage.


Can I tune to be good at both short & tight or long & fast without switching out springs & shocks or will it always be a compromise or happy medium/one or the other?
First, with today's range of adjustable shocks, it is possible to run the same shock ... on different settings & do well. When going from small, tight AutoX competition to a bigger, fast road course competition ... the things to typically change are spring rate, sway bar rate, roll center heights & just "tune" on the shock adjustments. (There are also other small adjustments to achieve optimum, such as brake bias, track width (think thin wheel spacers) toe/ackerman, slight changes in ride height and/or rake, etc.)

As I mentioned earlier ... ALL suspensions are a "compromise" ... to some degree. So I don't use that word to mean a bad thing, as it seems you may be. So I think as you get more knowledge & clarity, the better stated question would be ...

"Can I tune my car's suspension to be good at both short & tight corners and long & fast corners without switching out springs, sway bar rates & roll centers ... and outperform the other competitors?"
Yes ... and no.

Yes you can design, build & tune in your suspension set-up to be "pretty good" in that range of venues ... by setting it in the "middle" of the two optimum set-ups ... and outperform the other PT competitors there ... that are also not changing springs, sway bar rates & roll centers ... which today, would be "most."

But you're not going to outperform the guys & gals that are more hardcore, and came to that venue with the optimum set-up for that venue, then tuned on it all day to keep it "dialed in."

Make sense ?


It seems that the One Lap Camaro is doing it on both! I'm pretty sure that he won't give up his suspension tricks anytime soon...
There are no tricks or magic. I suspect he has worked out & dialed in a good overall set-up that works "good" at both types of venues ... and he is making tuning changes either through shock valving alone ... or potentially with adjustable sway bar rates too. Remember, he just has to beat all the other competitors that are also not changing springs, bars, etc.

The reason I ask is some of the courses are short & tight & some are longer & faster, & some include full on 100+mph sweepers. I would like to be able to quick change my setup if possible.
This is very possible, just accept the realities. If you want it to be "the best" ... you need to tune on it.

I'm not trying to steer you to a high travel/low roll set-up ... the suspension strategy is your decision. But below I'm outlining a high travel/low roll set-up for AutoX & then changes to make for high speed road courses. Since I primarily work with high travel/low roll set-ups these days, it's just easier for me to use this type of example.

SAMPLEAutoX set-up:
Front Spring Rate: 500# * Real rate would depend on motion ratio
Front Sway Bar Rate: 800#
Front Roll Center in Dive: 0"
Front Shock Setting Low Speed Rebound: Very Stiff
Front Shock Setting High Speed Rebound: Moderate
Front Shock Setting High Speed Compression: Soft
Rear Spring Rate: 300#
Rear Sway Bar Rate: 350#
Rear Roll Center: 8"
Rear Shock Setting Low Speed Rebound: Moderate
Rear Shock Setting High Speed Rebound: Soft
Rear Shock Setting High Speed Compression: Moderate


SAMPLE Road Course set-up with minor changes:
No springs or front roll center ... just adjustable sway bar rates, shocks & rear roll center (which is easy).

Front Spring Rate: 500# * Real rate would depend on motion ratio
Front Sway Bar Rate: 875#
Front Roll Center in Dive: 0"
Front Shock Setting Low Speed Rebound: Very Stiff
Front Shock Setting High Speed Rebound: Moderate
Front Shock Setting High Speed Compression: Stiff
Rear Spring Rate: 300#
Rear Sway Bar Rate: 400#
Rear Roll Center: 11"
Rear Shock Setting Low Speed Rebound: Moderate
Rear Shock Setting High Speed Rebound: Stiff
Rear Shock Setting High Speed Compression: Stiff


But, If we wanted to really optimize our Road Course set-up, it may look like this:

Front Spring Rate: 550# * Real rate would depend on motion ratio
Front Sway Bar Rate: 950#
Front Roll Center in Dive: 1.5"
Front Shock Setting Low Speed Rebound: Very Stiff
Front Shock Setting High Speed Rebound: Moderate
Front Shock Setting High Speed Compression: Moderate
Rear Spring Rate: 350#
Rear Sway Bar Rate: 450#
Rear Roll Center: 10"
Rear Shock Setting Low Speed Rebound: Moderate
Rear Shock Setting High Speed Rebound: Moderate
Rear Shock Setting High Speed Compression: Moderate


READERS! Please don't lock in on this SAMPLE set-up. It's just a SAMPLE so we could go through a hypothetical exercise & have this discussion. I have NO IDEA if it's right for your car & application. There are too many variables.

P.S. Josh, I know you're looking at running a wider track width. That helps make the car more versatile & less finicky about set-ups affecting the roll angle. So, that would be a very good move, to help you achieve your goals.

.

[Ron Sutton]

Speaking of cloudy. In our earlier conversations, I asked if the ATS spindle you have is the same as a C6 spindle for KPI. I talked to Blake and it is not. The ATS spindle has 8.0 degrees of KPI.

So to achieve the KPI/Caster split favoring the caster ... for optimum tight corner AutoX performance ... the caster needs to be around 9 to 9.25 degrees. There is more details to your steering set-up for us to discuss, so don't just lock in on that number by itself. I'm happy to help you work out an optimum set-up.

-------------------------------------------------------------------------------------------------------------------------------------------------

You know how people say a little information can be dangerous? This is one of those times.

If your car has a large-ish scrub radius … you have to be careful with how much caster you can put in the car … because caster combined with a high scrub radius creates a “jacking effect” when you turn the wheels. Dynamically, this jacking effect “de-wedges” the car … loading the inside front & outside rear tires more … while also unloading the inside rear tire & increasing the degree the car diagonally rocks & loads the outside front tire.

All of this helps the car to turn better. But go too far … and the car will get loose on entry. This is where track tuning comes into play. If you have a large-ish scrub radius … sneek up on the caster you put in the car … until you get the car “free” on entry … then reduce the caster a tick … or tune something else to allow you to keep that amount of caster, so the car turns well in the middle. But don’t keep a set-up that makes the rear step out on corner entry.

Make sense?

.

[diesel25lrs]

Ron,

Thank you very much for clarifying & taking the time to teach me! I was definitely a little "cloudy" but not anymore! The example setup really helped me see the #s on paper.

I understand there is a ton more to learn & test/tuning will be an ongoing thing. I just want to get the major components right the first time around which means i need to know which direction i intend to go with this.
I am still talking with a couple guys about widening my TW on the rear as this will be the major hurdle for matching F/R TW.
Also, thanks for clarifying the KPI on the ATS spindle. I was under the impression that C5/C6 were running same & this was a copy with modified steering arm mount location.... I'll have to do some research to find a spindle with a Caster in the 9-9.25 range unless you know off the top of your head who is making one for my car?

[BuickGS]

Ron,
You mentioned in a previous post that you use software to model your suspensions. Which one do you use? I am in the market for software. I am building an autocross/track day GM A-body car that will be barely street driven/legal. I have an aftermarket chassis, but would like to measure and confirm what my chassis company built before I put the body on it.
Thanks,
Jeff Peoples

[Ron Sutton]

I use several. Are you looking to just do the front suspension for roll center & camber gain, etc. ... or just the rear suspension ... or do you want to map every possible detail in the chassis?

The latter is harder to use. The first two are pretty simple.

[BuickGS]

Ron,
I would like the ability to model the front (double A arms) and rear (torque arm & watts link). Not really every possible detail of the remaining chassis.

[Ron Sutton]

Ron,
I would like the ability to model the front (double A arms) and rear (torque arm & watts link). Not really every possible detail of the remaining chassis.

Hi,

I prefer to recommend Performance Trends products for a few key reasons. I went & reviewed their different updated software versions ... and unfortunately, the less expensive, easy to use software options they offer do not map out the rear torque arm & watts link suspension.

So your options are to:

A. Get the full 3D version, which is more complex to use, mainly because you have to sort through a gazillion input options you won't use. Performance Trends software is the easiest to use of the complete, 3D software brand options, but that's like saying brain surgery is easier than rocket science. It's $400 & you can see it HERE (http://performancetrends.com/SuspAnzr.htm).

B. A better bet is to get their basic front suspension software, called Roll Center Calculator, which I highly recommend for car guys working out their roll center, camber gain, dive evaluations, etc. It is $79. Go HERE (http://performancetrends.com/rc.htm).

C. The best bet would be getting their "Roll Center Calculator PLUS" for $129 that includes rear suspension & overall handling calculations, which I think is important. But it doesn't have options for Torque arm & Watt's link. Frankly, you could fake* the information into the program quite easily & have a full suspension program for only $129. Same location (http://performancetrends.com/rc.htm).

* What I mean by fake the input info, is:
1. Choose a 3-link & input your lower trailing arms as normal (4 points) & make the top link achieve an instant center at the same dimension as your torque arm instant center.
2. Find the height of your Watt's link pivot and enter that number into the software for both sides of the panhard bar measurements. These simple softwares do not account for the PH bar arc anyway, so you'll end up with the correct geometry in the software ... and the ability to do full suspension calcs.

The FLLD calculation in the "Plus" is worth the price of the software all by itself, because you can work out combinations of roll center, spring rates & sway bar rates and KNOW how balanced the car will be. :woot:

.

[BuickGS]

Ron,
Performance Trends is the company I have been most focused on, as I have used their Engine Analyzer in the past. I was concerned about torque arm being a problem, so I like your work around for that. It sounds like "Plus" is one for me. Thank you for the advice.
By the way, here is my current car (that has me hooked and building a more serious effort)......

http://www.popularhotrodding.com/features/1110phr_1972_buick_gran_sport/

Jeff Peoples

[Ron Sutton]

Cool.

Awesome car. Keep us updated on your progress.

.

[Ron Sutton]

Ron,

Thank you very much for clarifying & taking the time to teach me! I was definitely a little "cloudy" but not anymore! The example setup really helped me see the #s on paper.

I understand there is a ton more to learn & test/tuning will be an ongoing thing. I just want to get the major components right the first time around which means i need to know which direction i intend to go with this.
I am still talking with a couple guys about widening my TW on the rear as this will be the major hurdle for matching F/R TW.
Also, thanks for clarifying the KPI on the ATS spindle. I was under the impression that C5/C6 were running same & this was a copy with modified steering arm mount location.... I'll have to do some research to find a spindle with a Caster in the 9-9.25 range unless you know off the top of your head who is making one for my car?

I prefer the ATS spindle with 8 degrees of KPI ... over the C6 spindle. The only reason to run higher KPI is when the front wheels are pushed out wide ... and the higher KPI helps reduce scrub radius. If the scrub radius wasn't an issue, you would run spindles with KPI in the 3 to 5 degree range.

For my personal car, I designed it with a "Long Arm/Zero Scrub" set-up ... with longer control arms, placing the ball joints & hubs quite far outward ... and using deep back spaced front wheels to achieve "zero scrub." The longer arms means the geometry changes less through it's travel & I travel the front wheels 6"+ on corner entry ... so that matters. I was able to achieve this with a 5 degree KPI spindle ... so I only need 6.0 to 6.5 degrees of caster to achieve the same KPI/Caster Split I recommended to you and many others.

So I think you should go with the ATS spindles (8* KPI) instead of C6 spindles ... and run the caster around 9.0-9.25. Make sense ??

[BuickGS]

Hey Ron,
Do you know the KPI of the stock 68-72 GM A-body spindle? I cannot find it online. I still have stock spindles on my 72 (although with tall ball joints), but have new ATS spindles still in the box. At the time I installed all of the aftermarket parts on my front end, the ATS spindles were back ordered for months. My car understeers in the autocross, and I am wondering if the ATS spindles (and lots of caster) would help.
Sorry to be hijacking this Camaro thread.

[diesel25lrs]

Hi Ron,

Makes perfect sense! I believe the only other option would be a custom built upright to get that 9+ KPI for my car...

So i'll plan on sticking with the ATS & building some longer arms once we work out the correct geometry to get my scrub down.

Theoretically, if i move my LCA ball joint pivot point out ,say 1.5", would the mounting points for steering arm & SB move same distance? The software should tell us these points as well right?

[Ron Sutton]

Hi Josh,


Hi Ron,

Makes perfect sense! I believe the only other option would be a custom built upright to get that 9+ KPI for my car...
I don't think you want 9 degrees intentionally, unless your wheels & tires are pushed outward & you're trying to reduce the scrub radius. I think I remember... (bad at my age) ... you saying your current hubs & brake rotors had the tires & wheels moved out ... and the ATS spindles would move your tires & wheels in 1" on each side.

Is that correct ?
What would that make your scrub radius?
If is it acceptable, I'd go with the ATS or another good spindle with 8 degree KPI.

So i'll plan on sticking with the ATS & building some longer arms once we work out the correct geometry to get my scrub down.
I don't remember what you're doing here. Are you going to front wheels with more back spacing that will require/allow you to run longer LCA's & move the BJ out for lower scrub radius?


Theoretically, if i move my LCA ball joint pivot point out ,say 1.5", would the mounting points for steering arm & SB move same distance? The software should tell us these points as well right?
There's no need for the steering box or pivots to move. Because when you run longer LCA's ... your LCA chassis pivot is in the same location. It doesn't move. Just the spindle & steering arm out on the end of the LCA move outward ... requiring a longer tie rod. The bump steer spacers don't even change "much".

Are you running a R&P or traditional steering box? Front or rear steer?

I'm looking forward to helping you pull together a plan & am reaching out to people I know there to find you a good fab guy.

.

[Ron Sutton]

I want to give you as complete of an answer as possible, but don't want to take this thread off track.

Please start a new thread titled: A-Body Spindle Question ... and post this text there ... along with your full real name. Thanks !!!

.

[diesel25lrs]

Hi Josh, Hi Ron, I just got back in from vacation and have some parts waiting for me! New ATS spindles, still waiting on the new brakes to fit them.


Makes perfect sense! I believe the only other option would be a custom built upright to get that 9+ KPI for my car...
I don't think you want 9 degrees intentionally, unless your wheels & tires are pushed outward & you're trying to reduce the scrub radius. I think I remember... (bad at my age) ... you saying your current hubs & brake rotors had the tires & wheels moved out ... and the ATS spindles would move your tires & wheels in 1" on each side.
Once I get the brakes in, I will measure everything up again and see how far this new setup moves my wheel in from current hub/stock spindle location. It should also make my scrub radius a little better. I'll post the new #s when I switch them out.

Is that correct ?
What would that make your scrub radius?
If is it acceptable, I'd go with the ATS or another good spindle with 8 degree KPI.

So i'll plan on sticking with the ATS & building some longer arms once we work out the correct geometry to get my scrub down.
I don't remember what you're doing here. Are you going to front wheels with more back spacing that will require/allow you to run longer LCA's & move the BJ out for lower scrub radius?
Yes, that is the plan! Once I get the new spindles on and take a really hard look at the widest tire I can put on there with mods(shooting for a 13" 325/19-may be a bit optimistic). I will be putting on the Anvil fenders which claim to be just over 1" from stock but possibly up to 1.25" outwards. I will be redesigning (lengthening) the control arms for better scrub and wheel clearance. The plan in my head right now is to push the wheel out as far as possible with new fenders and backspace rest of wheel/tire inwards all the way to the frame if I can package control arms, steering, and sway bar properly to fit "inside" wheel radius. I may even notch the frame a hair to get an extra .25-.5" wheel clearance if need be. These new lengths need to be worked out yet for proper geometry on software.

Theoretically, if i move my LCA ball joint pivot point out ,say 1.5", would the mounting points for steering arm & SB move same distance? The software should tell us these points as well right?
There's no need for the steering box or pivots to move. Because when you run longer LCA's ... your LCA chassis pivot is in the same location. It doesn't move. Just the spindle & steering arm out on the end of the LCA move outward ... requiring a longer tie rod. The bump steer spacers don't even change "much". Gotcha

Are you running a R&P or traditional steering box? Front or rear steer? R&P rear steer

I'm looking forward to helping you pull together a plan & am reaching out to people I know there to find you a good fab guy. Thanks much!

[Ron Sutton]

Okie Dokie.

Sounds good. Let me know when you get all the new parts on & measured.

.

[diesel25lrs]

Hi all,

So I'm not sure how I missed it but I finally made it through all of Lance's thread where Ron is working with him as well. Located here-https://www.pro-touring.com/showthread.php?98063-Need-a-little-help-figuring-something-out

I learned soooo much and it made my light bulb go off so much it looked like a disco in my room! It was everything I wondered about, didn't know, wanted to eventually ask and much more! I will be printing off many pages from that to put in a book!

So, an update on my situation...Car is still with my bud working on the cage. The new spindles arrived this week while I'm traveling for work and still waiting on the new C5 Brakeman brakes next week to put it all together. Once they are on, we will spend the day going through all the measurements and figuring out exactly how much tire we can stuff under the front with some minor mods. I spoke with Tracy yesterday at Anvil & the widened fenders are much wider than I thought at 1.5" over stock!!! This is good but....still have to go inwards a bit more for TW issues!

Not to change gears but since it still involves the suspension & will be another week or so until I can get Ron the measurements, I have a couple questions in the meantime.

During my reading, Herb Adams recommended heating the axle tubes to get a 1* toe in and -1* camber on the rears. I spoke with my buddy who races circle track and he recommended I take it to a shop with a rear end jig b/c if I get it more than 1/8" off, the axles may never come out...He also said he thought someone made some angled flanges specifically for this. Problem is I can't seem to find the angled flanges online?
Thoughts/Ideas?

This brings me to my next question...What are the Pros/Cons of a full floater rear end compared to a solid, how does it work, and does it differ from a semi-floater?
I know they are very pricey and out of my wheelhouse at this time but was told I can convert my solid axle strange 9" over for much less...

Have a great weekend!

[Ron Sutton]

Hi all,

So I'm not sure how I missed it but I finally made it through all of Lance's thread where Ron is working with him as well. Located here-https://www.pro-touring.com/showthread.php?98063-Need-a-little-help-figuring-something-out

I learned soooo much and it made my light bulb go off so much it looked like a disco in my room! It was everything I wondered about, didn't know, wanted to eventually ask and much more! I will be printing off many pages from that to put in a book!

So, an update on my situation...Car is still with my bud working on the cage. The new spindles arrived this week while I'm traveling for work and still waiting on the new C5 Brakeman brakes next week to put it all together. Once they are on, we will spend the day going through all the measurements and figuring out exactly how much tire we can stuff under the front with some minor mods. I spoke with Tracy yesterday at Anvil & the widened fenders are much wider than I thought at 1.5" over stock!!! This is good but....still have to go inwards a bit more for TW issues!

Not to change gears but since it still involves the suspension & will be another week or so until I can get Ron the measurements, I have a couple questions in the meantime.

During my reading, Herb Adams recommended heating the axle tubes to get a 1* toe in and -1* camber on the rears. I spoke with my buddy who races circle track and he recommended I take it to a shop with a rear end jig b/c if I get it more than 1/8" off, the axles may never come out...He also said he thought someone made some angled flanges specifically for this. Problem is I can't seem to find the angled flanges online?
Thoughts/Ideas?

This brings me to my next question...What are the Pros/Cons of a full floater rear end compared to a solid, how does it work, and does it differ from a semi-floater?
I know they are very pricey and out of my wheelhouse at this time but was told I can convert my solid axle strange 9" over for much less...

Have a great weekend!



Just about any 3" housing can be converted to full floating hubs. In my opinion ... in a mean street or track car ... full floating hubs are not "optional" ... but a necessity for safety & performance.

When you start driving a car HARD ...
a. Those flanged axles flex way more that you think. ... and that's dangerous.
b. That axle flange flex is the major contributor to brake "knock back" ... which can be scary & dangerous when you have to pump the brakes to get even braking force.
c. You are loading the ball bearings or open roller bearings with way more thrust load than they were meant to deal with.

Floater hubs put your mind at ease, because you know you have a strong structure back there.

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I believe the reason Herb said that about the toe, was to put slip angle in the tires, so they respond quicker & grip better. I do not know when exactly Herb made that statement, but I'm sure the tires of the day & the slip angle required to make them work played a role in the reason to run rear axle toe in.

But in my experience with today's short stiff, sidewall performance tires, that is less valuable. It is still being done in the road racing circles, and a few of them are actually toeing the rear out to make the car turn better. But I don't do that. We run ours zero toe.

As far as the camber ... yes ... 1/2°-1° negative camber will help work the rear tires more. Again, I don't do that, because it is so easy to get rear tire grip with suspension adjustments. Frankly it's easy to have too much rear grip, and we have to tune "out" rear grip to balance the car for neutral handling.

Like I always say ... it's your car. But I don't think you'll find any magic handling from this move.

I can't recommend the full floating hubs strongly enough. But your wheels need a hub centric hole 3.08" or bigger.

[Ron Sutton]

Hey Guys,

I'm going riding quads with my girls now ... so I'll catch up with everyone when I get back Monday.

Take care all !!! :cheers:

[diesel25lrs]

Spent the day making some new wooden cribbage boxes for this weekend. Got in the new tall uprights & Brakeman brakes. Going to switch all that out tomorrow & then start measuring my suspension geometry to start "fixing" things...

I ended up using 12 x 8' x2x4 for an 8 stack of 18" x14" boxes. Want a 13" wheel to fit comfortably!

Going to try & fab up an attachable metal wheel stud bracket & make it adjustable for the 2 front boxes, to be able to remove front wheels to measure.

[Ron Sutton]

Looking good. Keep us updated. :)

.

[diesel25lrs]

Hey Guys,
Sorry I haven't had any updates for awhile on this project...Deployments getting in the way of racing again...
Anyways- I'm back and had Thanksgiving off so I got a bit done..

I just got a killer deal on a full floater conversion for my 9". I went ahead and pulled the rear yesterday-which was supposed to be my day to measure suspension...I had to act fast on this one to get it shipped out to AZ to have the guy do it for me since he has the proper housing jig...Anyways, the measurements will have to wait a few weeks until I get the rear back in.
New ATS spindles and Brakeman brakes are on the front. Yesterday was the first time we had it on the ground and what a difference those uprights made over the old stock ones...I could really see a difference in the stance... without changing any shims from before, it sits about an inch lower and wheels went from -1.5 camber to about -4 just by changing those spindles. Once we get the rear back in, I'll adjust everything back to normal street setup and measure.
We also finished up the custom made front hub stands so we can measure the suspension without the wheels on at ride height. I'll post some pics of them later.

[Ron Sutton]

Hey Josh,

Thanks for the updates. Let me know when you need something.