‘87 IROC, completely stock chassis except new Koni struts and all bushings replaced with polyurethane. Only 32k miles on it, it sat at a collector’s for a LONG time….

At low speed with the steering wheel at full lock (either side), the front wheels scrub / hop (similar to what might happen if you locked a 4WD front diff and drove on pavement). The car was aligned and everything is within spec. However, the car did this before the new struts/bushings/alignment. Car tracks great at speed, doesn’t wander on the highway, steering box doesn’t feel loose at all.

Any ideas what to check?

Thanks,
Pete

 

I think there is a high percentage of 3rd gens that this happens to. I know mine did. I thought mine was because I have wide rims and tires with wheel spacers.
IMHO your problem is in the alignment and mainly the camber setting. The factory spec for these cars is + on the camber. When at full lock the tire is only riding on the small outside edge of the tire, causing it to "push" the tire rather than it rolling. As I said mine DID it also until just recently when I got new front tires and a new alignment. I had the shop change my camber setting to -.75 on the left and -.9 on the right. Slightly more on the right for the crown of the road. They made me sign a paper cause I wanted something different than factory specs. All I can say is now the scrub is gone and the wheel will kinda go with the turn now. I would check your alignment sheet to see where your camber is set.

 

My car does this too. Stock 16 inch wheels, stock ride height, alignment done, etc. I just ignore it because it rarely occurs.

 

It is normal for these cars. The Ackerman angles aren't correct. So they do the hop, skip, and jump on full lock low speed turns. I just do my best to avoid needing to do that steering input.

If your car doesn't have a steering brace (wonder bar), that I would install (Top-Down).

RBob.

 

All 3rd gens do that at low speeds.
you should feel my car on 315/30R18 race tires ha ha.
feels like the car is having a stroke.

​​​​​​GM messed up the steering geometry.
turns better left than right.

 

Changing to zero toe or just a smidge toe out will eliminate most that but then it will buck like a son of a gun in reverse instead of forward.

 

​​​​​​Good to know. Was scanning threads and this is one of those problems I have that I'll "get to someday". Lowered with 16" wheels.

 

Follow up: took the car to a performance shop. They checked over the suspension and did an alignment (had a tire shop do the alignment after I replaced struts & bushings).

Much better than it was, but still a small hint of scrub at full lock/low speed.

 

I appreciate the follow up and results.

Planning on koni struts shocks and subframe connectors this year so hoping a lot of that will alleviate a plethora of squeaks rattles and issues.

 

https://www.thirdgen.org/forums/susp...ml#post6460390

https://www.thirdgen.org/forums/susp...ml#post6356753