Ridetech bump steer

[beater65]

This is the early response from certifier, any help would be greatly appreciated.

"So you need to make the tapered holes the correct thickness material so theirs no welding etc , LVV (government agency) will want plans id say of the oe draglink and dimensions of your bolt on piece , id say what the question will be is raising the height of the inner pivots what extra leverage does that have on the oe draglink and connections to the pitman and idler ? id expect it to made out of steel.
I can do a stress analysis of new part, but really need to find OE steering loads?

Cheers

What really is crazy to me, is the amount of intelligent people they have doing these inspections, and how detailed they are in ensuring safety.

I've never heard of anything that in depth in the states, not saying there isn't. But still amazing. Guess it has its Pros and Cons

[Rod]

For comparison, I bumped an Art Morrison frame last week, with their steering arms, etc. +/- 2" of wheel travel from the ride height position I had +0.10 to -0.08" which isn't perfect, but it's reasonable for a street car.

the Morrison frame gets better when you add tall lower ball joints to raise the spindle and then move the rack upwards some

[Tweak]

Modeled the two options today to valuate the stress analysis of drag link and drag link with ridetech draglink attached.
With maximum force of 18500N applied to the tie rod.

[Mean 69]

One thing to look at is clearance to the oil pan, there have been reports of certain combinations not working together with the Tru-Turn, I think mainly with big blocks. But you might take a quick look as there is quite a difference in the inner tie rod height, probably won't help with packaging. Seems like you could reason with your officials by comparing the two pic's, of course it's all about the assumptions in forces, etc, but people love pretty FEA pictures (even if they are meaningless).

I agree that the rigor that your agencies put forth is admirable. In the US, the "inspections" are mainly for emissions testing rather than anything to do with safety. In California, it's borderline - no - completely ridiculous. So you can drive a total piece of crap with all kinds of safety issues, but as long as it "smogs," you are free to go out and endanger yourself and others.

Nice work,
Mark

[Tweak]

One thing to look at is clearance to the oil pan, there have been reports of certain combinations not working together with the Tru-Turn, I think mainly with big blocks. But you might take a quick look as there is quite a difference in the inner tie rod height, probably won't help with packaging. Seems like you could reason with your officials by comparing the two pic's, of course it's all about the assumptions in forces, etc, but people love pretty FEA pictures (even if they are meaningless).

I agree that the rigor that your agencies put forth is admirable. In the US, the "inspections" are mainly for emissions testing rather than anything to do with safety. In California, it's borderline - no - completely ridiculous. So you can drive a total piece of crap with all kinds of safety issues, but as long as it "smogs," you are free to go out and endanger yourself and others.

Nice work,
Mark

Hey Mark
Yes I have heard big block guys have all sorts of problems, especially with header fitment.
I'm using a GM Ls7 oil pan, so no issues for me as the bottom of the oil pan sits above drag link

[David Pozzi]

I've seen nothing on what loads GM may have designed for. Your bolt on plate should double the strength of the assembly and be more than enough. If you can prove your modified assembly is stronger than the stock one, it should pass. Most GM steering linkage is made of 1045 or 1046 steel, if that helps. There was a later center link produced in late 1969, it's thicker but softer steel, & probably not an improvement.

[Tweak]

I've seen nothing on what loads GM may have designed for. Your bolt on plate should double the strength of the assembly and be more than enough. If you can prove your modified assembly is stronger than the stock one, it should pass. Most GM steering linkage is made of 1045 or 1046 steel, if that helps. There was a later center link produced in late 1969, it's thicker but softer steel, & probably not an improvement.

Hey David
Yes that's great info, yes I'm with you and think it should be much stronger.
Do you by any chance have factory bump steer figures?

cheers
Damien

[Mean 69]

Great question on the OEM factory bump steer numbers, I suspect official numbers might be hard to find for argument with the authorities there. But it hopefully won't matter, I am pretty sure you will be able to beat the "old" numbers by a country mile with the new link and tuning. Keep in mind the tires back then were really skinny, floppy and rubber bushings galore - you could live with a significant amount of bump steer and never even know it. Now, with today's tires......

M

[David Pozzi]

I bump steered my 67 Camaro in the mid-70's. I had already done the Guldstrand mod, which made it worse. At something like 3" dive, I had over an inch of toe out.
Here are my measurements for a stock sub with stock steering, plus tall ball joints and tall outer tie rod ends: http://www.pozziracing.com/proforged_first_.htm

[Tweak]

I bump steered my 67 Camaro in the mid-70's. I had already done the Guldstrand mod, which made it worse. At something like 3" dive, I had over an inch of toe out.
Here are my measurements for a stock sub with stock steering, plus tall ball joints and tall outer tie rod ends: http://www.pozziracing.com/proforged_first_.htm

Have David
Cool. Great info
Cheers
Damo

[Tweak]

My final test jig. Worked out what height I wanted the inner tie rod, just wanted to lock in width.
Results were awesome, will post bump chart once I have done it

[brycedrue]

Wouldn't it be funny if a slight caster adjustment corrected the problem...

[Mean 69]

"Wouldn't it be funny if a slight caster adjustment corrected the problem..."

Extremely unlikely. I have been modelling a front setup over the last couple weeks, and in doing so comparing 5 degrees static caster to 8 degrees, over this relatively enormous range the toe error is very small. Very small. The amount of caster one can dial in to a stock frame using shims is nowhere near this range. Original poster is sharp and solving the problem the correct way.

Mark

[Tweak]

So in conclusion.
I think the ridetech concept is rock solid, as i have been able to tune my bump steer to better than there advertised figures.
The only problem is if you do not have the exact setup ridetech had when they developed there Try Turn (i.e.. Toe, Caster, Chamber, ride height) your results will be way off theirs.
For me I think what changes results the most is ride height, and we all have our preference for that.
Sorry my chart is in mm, thats how we role down here in New Zealand.
I was able to get almost zero change in bump through 3" of travel with the only bump happening in the last 1" both in rebound and compression.
I was able to get 5/64 of total bump steer in both full compression and full rebound. So 3/64 change on each wheel.
I would call that fantastic figures, but I'm sure experts on here would have there opinions?
I would like to thank all the people who contributed and offered advise as I was on a pretty step learning curve.
I would also like to thank Bret from Ridetech for being engaged, however I do feel you and your team offer defensive answers and aren't truely engaged in what it takes to truely fine tune a car.
In saying that I am very happy with my Ridetech package and would happily recommend there products.

I'm not an engineer, and don't clam to be. What I am is a qualified Industrial Designer that challengers everything. If I think is wrong, i work through good processes and find solutions that work for me.


Cheers again, damo

[dhutton]

So you’re saying that the ridetech Tru-Turn has worse bumpsteer than the original design? I am curious what caster and camber you are running when you took that data.

Don

[Mean 69]

Nice outcome, really good job. 5/64" translates to about 0.078. and while this isn't goo enough for a true race car on racing tires, you will be very hard pressed to notice this on the street or track with your setup.

I have to respectfully disagree with your conclusion however, within reasonable caster, camber figures the bump should have been better than what you originally had - and of course it can't be ride height either. So something is up. But nice job, you learned something, fixed a problem, and taught others as well.

That is a fantastic picture, it is really cool that the American cars appeal to other nations as well.

Cheers!
Mark

[slammed68]

not a chance in hell I would return my truturn setup for OE....something is off in your calculations or setup.

[dhutton]

Hopefully ridetech is busy trying to duplicate, analyze and understand what is going on here. That is just good engineering practice.....

Don

[Mean 69]

"not a chance in hell I would return my truturn setup for OE....something is off in your calculations or setup."

Brett and his team are really good, but I do ask if you have ever checked bump steer on your own car, assuming you have the setup? If you have, share the data please, if you haven't, and you like the way the car drives, then that's super cool but don't assume it doesn't have issues. Again, you can have error on a street driven car and it might not be horrible, but doesn't mean it's "right." Analogy - what if your timing was off by a few degrees in retard - you'd never know unless you use a dyno. If you have too much in advance, you would see it in detonation. Just because you can't feel it doesn't mean there isn't an issue.

M - out.

[slammed68]

"not a chance in hell I would return my truturn setup for OE....something is off in your calculations or setup."

Brett and his team are really good, but I do ask if you have ever checked bump steer on your own car, assuming you have the setup? If you have, share the data please, if you haven't, and you like the way the car drives, then that's super cool but don't assume it doesn't have issues. Again, you can have error on a street driven car and it might not be horrible, but doesn't mean it's "right." Analogy - what if your timing was off by a few degrees in retard - you'd never know unless you use a dyno. If you have too much in advance, you would see it in detonation. Just because you can't feel it doesn't mean there isn't an issue.

M - out.

With modern tires and stock suspension geometry the car was borderline dangerous with the amount of bump steer that was present. A dip in the road mid corner was terrifying. I have not taken bump steer measurements with the truturn setup but the improvement was drastic.

I never said that ridetech produced perfect bumpsteer geometry, There are too many variables built into these old rides for there to be a one size fits all solution that is perfect. His chart appears to show that ridetech geometry is terrible, I simply cannot however understand how it could be worse than factory unless the measurements or setup are incorrect. I dont think your analogy really applies to my statement. I disputed that the factory geometry has better bumpsteer than the truturn kit. Your analogy would imply that without measuring the factory geometry I would not be able to notice the bumpsteer. You can detect 1st gen bump steer from the passenger seat.