Bump Steer, Right Rear Tire Wear.

[obZidian]

A good friend of mine just picked up a Cobra. Besides the clutch feeling like you're trying kick through a concrete wall, the car is plenty fun.. even if it slower than my old car! hehehe!!

Anyways, on thing that I noticed is that she exhibits a good amount of bump steer which ALWAYS "bumps" or the rear "shifts" over the the right or the passenger side. With my old 98 camaro, she would do the same thing but that was with a SRA not an IRS. We had bump steer kits that realigned the suspension geometry and that helped out tremendously.

Also, besides the bump steer, the right rear tire is REALLY worn on the INSIDE of the tire ONLY. Tire pressure is fine and the left tire DOES NOT exhibit any of the wear the the right is showing.

I recommended that he check his rear alignment as it seems as if the camber and/or toe might be off. That alone might be able to help with the bump steer however, his car is lowered A LOT and I think the rear suspension might be off.

I apologize as I don't have much info on what mods it has but I do know that it is lowered, riding on bilsteins on stock Cobra wheels with spacers. (He purchased the car with all of these mods) The tires DO RUB even with a no passengers in it so the drop is probably like a sportline drop, not a prokit drop.. if that makes any sense.

Anyways, are there bump steer kits available for these cars and do they TRULY work?

Thanks.

 

[mu22stang]

Sounds like the camber is too aggressive.

As the rear compresses or droops (bump) the toe will change (steer). Bumpsteer adjustment kits will modify/correct excessive "steering" during suspension articulation by relocating the pickup points of the toe-rod ends. The 'bump' in bumpsteer has little to do with the car's reaction to driving over bumps or expansion joints. A stiff suspension and/or a bad alignment (which seems to be the case) is a more likely culprit.

Note: bumpsteer adjustments modify the alignment and vice versa.

 

[greengt88]

get some FTBR HD toe-links, and a Long Acre Racing Products Bumpsteer Guage. I need to do this to my car. I just installed a Bushing kit. i would also recommend doing the sway bar endlinks as well. You should also check the condition of the Wheel Bearings and check cross axis joints for play. You might as well you have to take the wheels off anyway right?

 

[obZidian]

fixed!!

Well... sorry about not getting to y'all sooner.

He got the car realigned and it seemed to have cured up all the issues, including the bump steer. No real tests yet but so far so good. I don't have the new alignment specs in front of me but the right was really negative compared to the left rear and the toe was off. Car hooks much, much better too interestngly enough but I'm assuming there is more tire on the ground now (less camber).

Thanks for the input. We were looking at the front sway bar today since the steering feels a tad loose. Both bushing on both sides look torn and/or badly worn. He wanted to swap the swaybar out and install some poly-bushings however, I'm not sure what sizes work on these cars for a street application. I'm assuming to balance the car it would be best to do both... though the rear sway bar looks very well hidden!

Any tips on which bars would he suficient to improve front end feel without making the too snappy?

A.

 

[svtjoe123]

I've heard nothing but good things about this front bar
Steeda Tubular Front Sway Bar (94-04 Mustang) at AmericanMuscle.com - Free Shipping!
The rear bar looks like a pain to replace and plus if he goes too big on the rear bar he could get oversteer issues, unless he's into that kind of thing. I'd suggest just a front bar with poly bushings and end links that are a little taller to compensate for the car being lowered.