Correcting bumpsteer with ball joints??

[cdrod]

Can I correct the bumpsteer on a '72 Olds 442 by using taller ball joints? I'm running a stock spindle and lower arm with SPC upper arms. I want to lower the car some and improve the factory suspension problems at the same time, so I was thinking of using +.5" lower BJ and +.9" upper BJ from Howe Racing. The +.5" lower BJ will effectively lower the steering arm by the same amount. Is this enough to correct the factory bumpsteer problem? Thanks!
Rodney

[David Pozzi]

A +5" taller lower BJ will lower the ball joint pivot relative to the steering arm. It would be the same as raising the steering arm .5", not lowering it.

[cdrod]

David:
Oops, got that backwards. Does raising the steering arm +.5" remedy the factory bump steer problem or is this too much?

[David Pozzi]

I'm not familiar with the 72 Olds suspension, but assume it's front steer & pretty much like a Chevelle. Does it toe in or out in bump?
If it toes in, you can loosen the idler arm at the frame & raise it. Same for the steering box, but you won't get as much.

[UMI Tech]

We sell 0.5 lower, 0.9 upper kits for A-body.

It is commonly accepted that a 0.5" lower ball joint moves bump steer toward reduction. I say commonly accepted (but not guaranteed) as there are a number of variables that can contribute and the only guaranteed method is to test on the exact car.


Can I correct the bumpsteer on a '72 Olds 442 by using taller ball joints? I'm running a stock spindle and lower arm with SPC upper arms. I want to lower the car some and improve the factory suspension problems at the same time, so I was thinking of using +.5" lower BJ and +.9" upper BJ from Howe Racing. The +.5" lower BJ will effectively lower the steering arm by the same amount. Is this enough to correct the factory bumpsteer problem? Thanks!
Rodney

[cdrod]

David:
The Olds is a GM A-body like the Chevelle, GTO, Skylark, etc. It is a front steer design, and my steering components are all stock pieces, i.e. tie rods, center link, idler arm. I'm using the stock lower A-arms and spindles with SPC adjustable upper arms to work with the taller BJs. I had a local shop rebuild the original gear box and PS pump; and they replaced the internals in the gear box to speed up the ratio to around 12:1. I don't know if the car toes in or out in bump, but I've seen some bump steer kits that bolt a plate onto the center link with higher mounting points for the inner tie rods to correct bump steer. This led me to research the topic and discover the Howe taller ball joints and the SPC arms to improve the camber curve. Everyone says the tall lower BJ will "improve" the inherent bump steer issues, but I haven't yet found any information as to how much adjustment is necessary. I'm not building a "canyon carver" or auto-cross car just trying to update an classic car to have a mild PT stance and more modern braking and handling.

Ramey:
Thanks for the info on your BJ kits. It sounds like +.5" lower BJ is considered the starting point and further improvements can be found by measuring if you want to diagram the suspension or dial it in with one of the computer software programs.

[csouth]

cdrod, have you reached out to Mark at SC&C? He was one of the people that helped bring the SPC A body arms to fruition. He can definitely tell you what combination should help cure some of the bump steer issues inherent to A Bodies.
Not sure where you purchased your arms and ball joints, but he's always inclined to help whether you purchased from him or not.

http://scandc.com/new/

[David Pozzi]

I agree, - contact Mark for advice. I think some of the bump steer kits are intended for the spindle swap to the later one-piece spindles. They cause bump steer issues due to the shorter steering arm and I think the tie rod height causes issues with that swap.

[cdrod]

I sent an email to Mark with my questions. Thanks for everyone's assistance.

[csouth]

I sent an email to Mark with my questions. Thanks for everyone's assistance.

Not trying to be funny but he's pretty easy to access by phone most days just have a pen and paper handy to take notes.

[cdrod]

Well, I don't think Mark will be chiming in on my this thread. I sent him an email describing my set-up and posed my questions, I received a reply stating that he couldn't find my name in their customer database and wondering if I had purchased from them in the past (which I haven't...but I did buy Mark's book on muscle car suspensions). I can't say that I'm surprised, or upset; he's got to make a living and handing out free advice without making a sale is really not the best business model! Although, my car is comprised of a hodge-podge collection of close-out deals and budget-priced parts so I'm pretty sure I'll need to tweak things once I get my car on the ground and running. Probably need better springs or lowering springs and maybe some rear control arms, shocks, etc.

[rickpaw]

You may get a different response from Mark via a phone call. I called Mark one time asking questions regarding the suspensions for my 67 Firebird, and we talked for 1/2 an hour. Granted I did purchase some control arms from Mark about 2 months later.

[David Pozzi]

Can you measure toe in? If so, measure it with the cars weight on it's wheels, jack it up 2" and measure again.
The ideal way is to add weight to the front to push the car down 2" since we care more about bump toe changes. Open the hood, place some cardboard or rags on the fenders and core support and stack some heavy stuff on there. You really need something to act like turntables to reduce tire to floor friction. I've heard multiple layers of greased wax paper works. This will tell you if you even have a problem.

[csouth]

You may get a different response from Mark via a phone call. I called Mark one time asking questions regarding the suspensions for my 67 Firebird, and we talked for 1/2 an hour. Granted I did purchase some control arms from Mark about 2 months later.

I'll have to agree with you on that. I've never heard of him turning away a good phone support session. Besides I feel that conversation would be best had over the phone versus multiple emails. The OP seems opposed to calling him.

[cdrod]

David:
I don't have the car on the ground yet. I'm doing a frame-off resto/mod and haven't installed the body or the springs either, so I can probably measure the toe change while it's on jack stands. I'm not quite sure how to simulate the final ride height with the frame on jack stands, but it certainly seems doable.

csouth: I will try to give Mark a call sometime during business hours this week to discuss my bump steer questions.