6 replies to this topic

[Maniac motorsports12]

I have been asking a lot of questions and not getting any answers, I am hoping someone on here can give me some good direction. I am wondering how much of a problem bump steer is with the 99s? What are people doing to correct it in both the front and the rear, if anything? I tried to use the longacre bump steer gauge, but it really is not made for our cars, and very difficult to get an true reading.

[Tom Sager]

You should get better opinions here than mine but here is some info that might help. I doubt that anyone on this forum will mention that there is a bump steer issue on the rear of any of the cars '90 and up. The '99 has updated front subframe and steering knuckles compared to the older cars which I believe all but eliminates bump steer on the front so I don't think you have any worries at all on your car. One way that we checked bump steer on my car was on a modern alignment rack. We set the toe and then measured toe change as we moved the steering in either direction while jacking the car on one side to simulate cornering attitude. The results confirmed what others had said. That car is a '95 and we did find a big front toe change when doing that.

[Jim Drago]

There is nothing you can do legally to address bumpsteer in a SM
Jim

[Ron Alan]

Based on Tom's comments and then Jim's...my understanding of what is "bumpsteer" just went out the window. Can someone give a basic definition or maybe link an article?

[Bench Racer]

Based on Tom's comments and then Jim's...my understanding of what is "bumpsteer" just went out the window. Can someone give a basic definition or maybe link an article?

http://www.longacrer...rt.asp?ARTID=13

Per nasa:

16.3. Steering rack on 1990-97 cars may be shimmed between the rack and subframe at its two

mounting locations. Each rack mount utilizes two bolts; both bolts must pass through each shim

at that location. Shims must be the same dimensions and be made from aluminum or steel.

Total thickness of shims can not exceed 12.70mm (0.50 inch) in thinness/width.

[MPR22]

David's article explains the mechanics of bump steer.
I notice the bump steer in my 1.6 in high speed carousel type turns. The 99 is much more stable.

[Jim Drago]

David's article explains the mechanics of bump steer.
I notice the bump steer in my 1.6 in high speed carousel type turns. The 99 is much more stable.

That is a myth... Just go back and search all the old threads on it! It is the difference of the rigidity of the platforms, it has nothing to do with bumpsteer!