True benefits of swapping to tubular control arms ???

[CreepinDeth]

I've been wondering what the real benefits are for swapping to tubular control arms
on my 1970 Olds 442. Is it really worth all the effort for a street driven car ??

Been debating this issue.
I got SC&C adj UCA's for my 2nd gen Camaro which allow for camber/caster/etc adjustments.
However with tubulars I'm just in the dark on the cost to benefit ratio.

Can anyone shine some light on this ??
49243

[knucklebusted]

I've got a set on my '70 Buick Stage1 GS.

All of this is generally speaking. Tubular arms are usually more rigid, have alternative bushings that are more solid than factory rubber. Most will also add several degrees of positive caster for better handling.

One of the things I found is they are NOT lighter. The lowers were about 3lbs heavier and the uppers were about a wash.

[BonzoHansen]

it's all about improved geometry with the good ones. make old cars much better drivers with big modern tires.

[JRouche]

I like all the responses. But IMO you can also get some great performance for the street car using stock CAs if you completely rebuild them, new bushings (I like delrin, but new rubber bushings are a world of diff from wore out rubber bushings, I dont like poly bushings). And new ball joints. AND!! A new alignment!!! Thats a biggy.. Its gonna have to be a custom alignment from a shop (or yourself) to get the most out of the tires that you are using. Cant drive up to Firestone and ask for an alignment. They will look it up on the computer and stuff the OLD numbers in there.

I have a couple of odd car alignments and before I started doing my own I was lucky to have someone recommend a shop to me. There is this long haired biker looking guy doing the alignments, he was recommended by name, Jim. I gave him my story on how the car was modified and he knew exactly what to do. He never looked up any numbers. He aligned it and when I drove off it was like a new car.

He is a treasure and not common to find in most cities. So I ended up doing my own alignments on my "odd" cars. And for the cost of a decent alignment I was able to make a set of tools to do it in my garage.

Some old cars have to use different alignment numbers to make them work with the modern tires and suspensions. So you think, where to start for alignment numbers? Well, some checking around with folks that have similar cars is ok, but alot of times they will be running the "book" numbers that was in place when the car was made.

Its a good starting point but to get the most from it will mean playing with several alignment configurations. And that can be too much to deal with for some folks. I get that. They want to have it aligned and be done with it.

Easiest way? Do some massive research for alignment numbers for your car (stock arms) and find a happy medium. Then find an independent tire shop that does alignments and see if their man can work without the book. If so give him your desired Camber, caster, toe numbers and see if he can work out of the box. The diff between a common tire shop (goodyear, firestone and the like) and an independent shop might make the world of diff for your car. JR

[Marcus SC&C]

Aftermarket A arms are often misunderstood. Marketing has a lot to do with that. The A arms are a critical part, you can`t drive around without them, but the role they play in geometry and performance is not a leading role it is a supporting one. Replacing stamped OE arms with tubular duplicates yields no tangible improvements, why would it? If you do what you`ve always done , you`ll get what you always got.
That said aftermarket A arms are an absolutely necessary part of any well thought out performance suspension package. Why? Because most muscle cars and certainly the A body mentioned in the original post here have horrific suspension and steering geometry. It`s not just, not as good as a new car, it`s totally backward. It`s literally worse than a horse drawn wagon, no kidding! Now, we can tune this turkey all we want and we`ll make some small gains but the big problems will still be there (we didn`t fix them) so we`ll spend a lot of money on it but we will still have a car that drives poorly by any modern standard.
So, the smart thing to do it fix what`s wrong with it and THEN tune it. Backward camber curves, ultra low and very unstable roll center, massive bumpsteer etc. all need attention. We can use the appropriate tall spindles, tall ball joint package etc. to correct the geometry and bumpsteer issues by relocating the suspension pickup points to correct locations and take some truly massive strides forward. Now we have a solid foundation to build on and tune. So we go to set the alignment with more modern specs and we can`t....why? The stock upper A arms are now the totally wrong length, offset and angle to work with the new geometry and alignment. No suprise, after all they were designed for a totally different system. This is why we change the upper A arms! Arms with the correct specs for the new geometry will make it easy to set the new alignment and will have safe and proper travel. Now we have a true package with components that work together properly.
What about the lower A arms? Different story. On this platform (A body) the LCAs aren`t capable of being a game changer...but...we can still get some benefits from them. The stock lower A arms were designed for a mild application car with little tires and brakes and no handling ability that it was aware of. They were fine for that. Now, nearly half a century later they`ve been through millions of fatigue cycles, potholes, curb shots etc. and we`re going to ask them to hold up to much larger stickier tires, much better brakes and twice the handling ability...without failing. Do you feel lucky? Oh and lets not forget their usual mode of failure, it resembles a train wreck and you crash violently. Hmmm. It`s a very good idea to at LEAST closely inspect them and check them from time to time for stress cracks etc. I have some pics of lower A arms failures in my book (How to Make Your Musclecar Handle) and it ain`t pretty. So, a stronger set of lowers is a good idea! While we`re at it we can improve the bushings (greasable delrin would be nice) and maybe make some other tweaks. A good example are SPC LCAs with modular adjustable spring pockets to adjust ride height and geometry build around a modern alignment for maximized tire clearance etc.
To summarize, do tubular upper A arms do anything by themselves? Yes, they look cool and they can (depending on the arms) allow a better static alignment but that`s all.
Do lowers do anything? Yes, they replace old weak parts with new ones that may be stronger. Sometimes they can have other complimentary features such as coil over mounts or adj. spring seats.
Do you need tubular A arms? No...unless you do. If you`re happy with the car stock, no. If you`d like to be able to run a more modern alignment, need to accomodate corrected geometry or want more strength and durability...then yes. Just make sure to do your homework and make sure you get arms that actually do what you need them to do as some of them are only a cosmetic modification. Mark SC&C

[Tony_SS]

Especially with running larger, wider wheels with a high performance tire. All the grip transfers stress on the arms/bushings.. I'll take an aftermarket setup over the stock, stamped one.

[ponchopwr70]

What Marc said. Also stock lower arms can be fatigued and can crack especially with a lot of tire and grip.

[BulldawgMusclecars]

Mark made some excellent points, and I completely agree with him. I wanted to add, though, that control arms aren't a place to skimp. There are too many manufacturers of suspension parts out there that are little more than a few guys behind their house with a MIG and a pile of steel, with no engineering background, no real understanding of the physics, the metallurgy, etc. About 10 years ago, I bought a set of tubular lower control arms for a 3rd gen F-body, from a well-known supplier, and in less than 3 months of careful street driving one of the tubes broke as the car was about to merge onto a busy interstate highway. The supplier was known for drag racing suspension parts, particularly in the 5.0 Mustang world, but had told us their arms were designed for street use. We were lucky, in that it was obvious something was wrong and we stopped immediately to check it out, but lives could have been lost had it broken a few seconds later. That said, I don't think you can go wrong with most of the higher end manufacturers, but I wouldn't put any of the bargain basement control arms out there on my lawn mower. Just because it has the same shiny powdercoat and the same type bushings doesn't make them equal.

[JEFFTATE]

As always , Marcus knows his stuff.

[Henesian]

I have the Pro-touring F-Body upper control arms w/ tall BJs on my 76 T/A, and the car handles way better with them, than my old stock uppers, because they have +5 degrees caster and -0.5* negative camber with no shims, with a great camber curve with tall BJs. I think if you buy arms from any of these pro-touring sponsors(DSE, Hotchkis, Ridetech, Global West, etc.), they'll have tuned in enough offset to make it worth the money.

However, it is possible for tubular control arms to have no caster/camber benefit over your stock arms. What determines the positive caster an arm gives you is the "Offset" of the arms. If looking from the front of the car down to the rest of the car, the arm closest to you is angled in a way to push the wheels back. That gives you positive caster.

If an arm has "zero" offset, and stock length balljoints, stock arm length, then it's just as good as your stock stamped arms. Some circle track arms for the stock Camaro body are like this.

Also, another fun note. No weight savings over the stock ones. My stock uppers were light as hell.

https://static1.pt-content.com/images/pt/2011/09/IMAG0171-1.jpg
https://static1.pt-content.com/images/pt/2011/09/IMAG0191-1.jpg

[CFster]

I wouldn't have changed mine if I hadn't gone with my "tall" ATX spindles. IMO it's only worth the money if you're changing geometry.

[CreepinDeth]

Thanks so far guys.
Marcus, that post was so in depth you almost confused the crap out of me even further. LOL
I do understand my aged control arms are probably in need of replacement hence why I was inquiring.
I wasn't aware that these offer THAT much better modern car suspension travel and things of that nature tho.

I just wasnt' sure if I should go with the bargain basement updates or grab some higher end parts again.
The cost is prohibitive on the higher end stuff and I'm just not going to autocross this car or anything serious.
However, from the way you're describing the A-body's suspension it sounds like it's absolutely abhorrent as is.
I'd like to really see how it compares to these improved setups to justify the $$$ is what it boils down to for me.

I already have the UMI roto joint rear adj UCA's in my A-body, so a full blown kit unfortunately won't be an option.
I have zero clue on how to match suspension components.
I'm going to assume I need the front and rear sway bar setups as well. I think I'll have to call and talk with you again.

Bulldawg, that's what I'm trying to avoid here. I'm not sure where these Ebay specials engineering came from.
So I'm not interested in buying from them at all. I'm mainly looking at SC&C, Hotchkis, UMI, BMR, and whoever else has a solid rep.

This UMI Delrin combo setup is pricey, but if it's going to VASTLY improve the handling of the car, I'd like to do it or from SC&C or another vendor.
http://www.umiperformance.com/catalog/index.php?main_page=product_info&cPath=2_251&products_id=538


IMO it's only worth the money if you're changing geometry.

Not sure I understand what geometry i would change.....?? Ride height you mean ??

[CFster]

Marcus talked about the backwards camber curve these cars have. Meaning, when the wheel moves up the top of the wheel tilts out (positive camber), which is exactly backwards from what you want. By moving the upper control arm pick up points (specifically upper ball joint location) this can be reversed, so the top of the wheel tilts in which keeps the tire square to the ground when cornering. This is accomplished by raising that upper ball joint location. There are different ways of doing it, but I use ATX spindles (one of the most expensive ways btw). There are other options. It's really changing the entire suspension geometry to be similar to a modern day vehicle. Other benefits are decreased bump steer from factory, increased positive caster adjustment and getting the roll center up where it's supposed to be from about 2ft underground.

Huge improvement.

[CFster]

BTW, SC&C doesn't manufacture parts, though Marcus has worked with companies to design parts. He's pretty much the authority on a-body suspension. Anyway, SC&C puts together kits of all the best parts from different manufacturers to give you the perfect package.

If you want to really learn about this stuff then call Marcus, but be ready to have some free time on your hands. The guy can talk!

[Norm Peterson]

Marcus talked about the backwards camber curve these cars have. Meaning, when the wheel moves up the top of the wheel tilts out (positive camber), which is exactly backwards from what you want. By moving the upper control arm pick up points (specifically upper ball joint location) this can be reversed, so the top of the wheel tilts in which keeps the tire square to the ground when cornering.
Just to simplify this a little more, when the top of the tire is allowed to tilt outward as it moves upward, the end result is heavier understeer that gets progressively heavier the harder you corner. The outward tilt of the tire is adding to the roll angle that the car develops, and both are getting worse as you drive harder. You end up cornering on only the outer tread blocks of the front tires (and perhaps partway up the sidewall), which is hard on tires and not particularly satisfying from the driver's seat.

This is considered "safe" suspension tuning for your average lowest-common-denominator driver, but you eventually get the feeling that whatever cornering performance you are getting is in spite of the suspension's shortcomings rather than because of any goodness.

Making the camber change oppose the roll instead of adding to it is what the geometry change is all about.


If you were to run extremely stiff springs up front - as you might be tempted to do with the OE geometry just to keep it from moving very much and doing the bad camber thing - tubular lower arms that are stiffer than the OE stampings would be of some benefit because of that extra stiffness. You'd have to make sure that the tubular arms were in fact stiffer than the stampings, though. Just being tubular does not guarantee being stiffer, and dragstrip-oriented stuff could very well be less stiff than OE.


Norm

[Hotchkis]

There’s a lot of good information here. There’s not much more to say about A-body suspension and control arms without getting in depth into engineering.

We’ve been designing and building A-body suspension components way before other manufacturers gave them the time of day. Our A-body customers are happy with the results.

Here’s an A-body we upgraded with a TVS suspension package. Notice the before and after attitude of the car.


http://www.youtube.com/watch?v=kV1hbUI_MW4

[armourmark]

Hotchkis really has a good thing with that TVS kit for guys to do a complete suspension makeover on their own without having to mix and match parts. Proof is in the pudding. Totally different car now.

[Hotchkis]

Armourmark – Thanks for the kind words! It is nice to have everything in one package that’s designed to work together in harmony. :)

[CFster]

Hotchkis, how do you solve the camber curve problem? Tall ball joints?

[Hotchkis]

Hotchkis, how do you solve the camber curve problem? Tall ball joints?

In the past, we used to use the B-Body Impala type tall spindle with a different B-Body spindle specific upper A-Arm. That solved the camber curve issue but also increased turning radius. We still offer that solution but it isn’t as popular any more. Far more popular is our newer A-body spindle A-arm, which has an offset cross shaft which helps improve camber curve, plus we build in as much caster as possible while sticking with the stock spindle. We also now offer extremely high quality tall upper balljoints K-5108-SP (http://www.hotchkis.net/tall_upper_balljoint_af_body.html), which also help tremendously.

https://static1.pt-content.com/images/noimg.gif

[Derek69SS]

an offset cross shaft which helps improve camber curve

How? Does it move the pickup points downward? If so, how much? Seems to me, there's not enough room on an A-body chassis to move the upper pickups downward enough to actually fix the backward geometry.

[Hotchkis]

How? Does it move the pickup points downward? If so, how much? Seems to me, there's not enough room on an A-body chassis to move the upper pickups downward enough to actually fix the backward geometry.


Derek – the offset cross shaft offsets the Hotchkis (http://www.hotchkis.net/) control arm towards the engine to increase negative camber upon compression of the suspension. The taller upper ball joint essentially ads height to the spindle and greatly improves the negative camber gain.

You can see the offset cross shaft in this image of our upper control arms. :)

https://static1.pt-content.com/images/noimg.gif

[CreepinDeth]

There’s a lot of good information here. There’s not much more to say about A-body suspension and control arms without getting in depth into engineering.

We’ve been designing and building A-body suspension components way before other manufacturers gave them the time of day. Our A-body customers are happy with the results.

Here’s an A-body we upgraded with a TVS suspension package. Notice the before and after attitude of the car.


http://www.youtube.com/watch?v=kV1hbUI_MW4

WOW......now that is exactly what I wanted to see. A VISUAL to see the difference.
"Almost a 20 to 1 steering ratio box" .....I heard factory was 16 to 1

I already have the Hotchkis TVS system with HPS1000 shocks on my 78z28.
Now I can see how much better it really is.

Can you PM me a price on what's all in that video for that A-body's suspension you guys swapped out to get that end result ??

It looks like some extra's were put on that A-body though.....I'm curious what the total package in that video runs.

[Derek69SS]

Derek – the offset cross shaft offsets the Hotchkis (http://www.hotchkis.net/) control arm towards the engine to increase negative camber upon compression of the suspension.That's not possible. Offsetting the pickups inboard creates a longer arm, which only slows the camber change. Camber will still go positive, it just won't go quite as far or as quickly in the wrong direction.


The taller upper ball joint essentially ads height to the spindle and greatly improves the negative camber gain.
That will help a lot, but if it's less than an inch taller than stock, it's still not enough to get a good camber curve.

[Hotchkis]

That's not possible. Offsetting the pickups inboard creates a longer arm, which only slows the camber change. Camber will still go positive, it just won't go quite as far or as quickly in the wrong direction.


That will help a lot, but if it's less than an inch taller than stock, it's still not enough to get a good camber curve.


Derek69SS – Moving the upper control arm shaft pivot point closer to the engine essentially shortens the upper control arm (from the stock location) which will in-turn pulls the top of the spindle inward faster during suspension compression.

With the combination of increased caster adjustment, the offset control arm shaft and the additional taller ball joint, it puts the suspension in a much better camber curve and handling characteristics than in stock form…definitely enough to consider it a good camber curve. Is it perfect? No, but it’s a huge improvement over stock and still allows the builder to retain his factory spindle and the tight factory turning radius, all with bolt-on parts.

[Derek69SS]

Derek69SS – Moving the upper control arm shaft pivot point closer to the engine essentially shortens the upper control arm (from the stock location) which will in-turn pulls the top of the spindle inward faster during suspension compression.

With the combination of increased caster adjustment, the offset control arm shaft and the additional taller ball joint, it puts the suspension in a much better camber curve and handling characteristics than in stock form…definitely enough to consider it a good camber curve. Is it perfect? No, but it’s a huge improvement over stock and still allows the builder to retain his factory spindle and the tight factory turning radius, all with bolt-on parts.
Moving the pickups inboard would place them farther from the balljoint, so you'd need a longer arm, which slows and reduces the camber change through the suspension's travel. It does nothing to change the direction of the camber-change, which stock-spindle A-bodies so desperately need because their camber-curve is backward.

To change the direction of the camber-change, you need a taller effective spindle-height. Assuming your tall balljoints are around 1/2" taller, it might just be enough to bring the arms near parallel... certainly not enough to get much, if any camber-gain.

Reducing camber loss =/= increasing camber gain.

[Norm Peterson]

I think what I'm hearing is that moving the chassis side pivot laterally inward allows an effectively taller knuckle without driving the static camber setting into positive. That's a good thing statically, but what it is overall is a snapshot of the one suspension position that it won't be in as you accelerate, brake and turn corners.

Camber GAIN would be better served by a shorter UCA that mounts the chassis side pivot axis in the OE location, short enough to allow the same static negative camber setting.


Norm