Bump steer

[BILL]

Are we allowed to do any thing to correct bump steer on an ITB Mustang?

[Matt93SE]

Your best action is to not lower the car so much that bumpsteer is an issue.

[Ron Earp]

Bingo. That and follow the old adage "Any suspension will work as long as you don't let it".

[jimbbski]

Just asking a question here: Couldn't you consider the steering system on a rack-n-pinion steering system part of the suspension? The tie rod is a link in the suspension and it's connected to the rack which is connected to the K member with bushings. And since suspension bushings are free in IT then couldn't you take it to the point where you can use offset bushing to try to correct bump steer? Dicuss.

I owned and raced a Fox Mustang and know the issues of bump steer. I didn't race it in IT so I was able to correct it using the more common heim joints in lew of tie rod ends method rather then offset rack bushings.

[Ron Earp]

I suspect that is a bit of a tortured interpretation. The GCR defines suspension bushing as:


Suspension Bushing – A hollow cylindrical mounting component which
acts as a bearing, allowing constrained motion, between a suspension
component and attachment point.

The IT bushing language is:


Bushing material, including that used to mount a suspension
subframe to the chassis, is unrestricted. This includes
the use of spherical bearings, so long as no suspension
component is modified to facilitate their installation. Retention
of spherical bearings by use of tack welds is allowed,
as long as the welds serve no other purpose.

And that language is under "Suspension Mounting Points". Steering is not specifically mentioned or called out, but, steering as defined in the GCR is a bit weak and doesn't specifically cite the rack.

[Matt93SE]

There was something going around about that thought process a few months ago. basically, as Ron said, it's a tortured interpretation and I would expect some feedback about it.

[Gary L]

Just asking a question here: Couldn't you consider the steering system on a rack-n-pinion steering system part of the suspension? The tie rod is a link in the suspension and it's connected to the rack which is connected to the K member with bushings....

I don't know how you came to the conclusion that the tie rod is a link in the suspension, but I disagree. You can leave the tie rod laying on the shop floor and still have fully functional "suspension", as defined in the GCR technical glossary - "A mechanical system of components controlling vertical motion and connecting the axle housing and wheels to the chassis of a car."

IMO, the tie rod does not meet the first of two requirements in that definition.

[manny]

yes there is a kit out there to correct the issue of bump steering in a lowered mustang. it looks like a spacer between the tie rod end and the steering knuckle.

[JeffYoung]

yes there is a kit out there to correct the issue of bump steering in a lowered mustang. it looks like a spacer between the tie rod end and the steering knuckle.

And is illegal.

[Flyinglizard]

Optimize the rack mount bushings and Subframe bushings. Not all steering arms are straight . Maybe yours are bent? Not all tie rods are the same , maybe you have short studs? Maybe there are longer stud tie rods. 5/8 fine thread I think.
Read the rules as far as rack placement, tie rod ends, lower control arm bushings. Just moving the lower point a little will help. "Tolerance stack" is what you want to do. Move all of these points the legal maximum amount.
Lower is faster, deal with the bump/ The mustangs can be pretty bad. I fix a bunch of the street rods that are way off, and raced a bunch of circle burners..
IMHO. MM

[BILL]

I thought I read somewhere that some year of tierod end was better for this but naturally I can't remember.

[jimbbski]

I owned and raced a 1993 Cobra "R" for a few years and the OEM tie rod ends on these cars were not the normal Mustang ones. If fact you can find then on most any Taurus of similar year production.
I know this because my Mom's 1995 Taurus has the same tie rod end as my "R". They were used by Ford SVT to "improve the bump steer" as the car was lower then a normal Mustang or Cobra.