O.K., the "search" function didn't address my question so here goes.

I have replaced the wheels on my '88 with custom 16"s. Resulting overall diameter is probably less than factory 14" due to the ZR50 tires I have installed.

After this installation, I have noticed a quite pronounced "bump steer" that was not evidenced with the factory stock 14" 70 series tires. My front end (and rear) have been recently aligned properly. I do not need any front or rear suspension parts replaced(except the steering rack bushing is very slightly loose on the inner tie rod). Front shocks are virtually new (less than 7,000 miles).

Now, anyone have any suggestions as to how to tame this bump steer?

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[This message has been edited by Rainman (edited 03-02-2004).]

I went to 205/40/17 on my '88. The ride was so rough (felt like bump steer) that I went back to my 216/60/15.

By "bump steer", I'm guessing you mean that the wheel kicks back when you hit bumps and holes in the road.
That is probably caused by the new wheels being offset further from the centerline of the car than the originals. You might be able to have more caster dialed in to the alignment settings. That will make the car harder to deflect from traveling in a straight line.
About the only other thing you can do is get narrower tires, or rims with more offset (IOW, they tuck in towards the center of the car, more.)

------------------
Raydar
88 3.4 coupe.

Coming soon...
88 Formula, presently under the knife.

quote Originally posted by Raydar: By "bump steer", I'm guessing you mean that the wheel kicks back when you hit bumps and holes in the road. That is probably caused by the new wheels being offset further from the centerline of the car than the originals. You might be able to have more caster dialed in to the alignment settings. That will make the car harder to deflect from traveling in a straight line. About the only other thing you can do is get narrower tires, or rims with more offset (IOW, they tuck in towards the center of the car, more.)

I'll second Raydar on this.

I have the 7 inch wheels with 225/50 15 tires on the front of my 88 GT T-TOP, and I get quite a bit of kickback in the steering wheel. This only happened after I installed those wheels and tires.

quote Originally posted by JohnF:

I really doubt you are experiancing bump steer, your description sounds nothing like bumpsteer. I bet a majprity of Fiero owners ( 84-87) have never experianced a good shot of bump steer. I've been driving Fiero's since the late 80's and I've only once ever got into a situation where there was a enough bumpsteer in a 87 GT where I felt it and then relised what it was, and that was only a few years ago.

Just stick your old front 14 inchers back on and see how the car feels.

[This message has been edited by jelly2m8 (edited 03-02-2004).]

Sheeesh, four good replies in less than a couple of hours. I love this place!

Thanks for the replies.

Now, would a steering stabilizer like on the older cars help? If so, where do I get one.

You sell 'em to me, and I'll put 'em on my car and see if we have the same problem

- or - not sell 'em to me and we'll mount them up as an extended temporary experiment!

You may not need one, but an alignment might possibly be in order. I have noticed that just small changes in my alignment have VERY dramatic affects on my cars handeling. Don't know if that has any impact on what you are feeling though...

I would have to agree with the wheel offset/width change creating more "kickback" to the steering wheel. When the front wheels move outward or the front tires are wider than stock, the moment arm/leverage of the wheel is increased. This results in a stronger "kickback" to the steering wheel when the front wheel/tire encounters a bump.

A damper might help, but the 88's have no mounting provisions for one, and it will (theoretically) also slightly increase the turning effort required to turn the wheels.

I tossed my daughter's 205/55/16 Michelins on my Fiero for about a month. That has been the best combo hands down. Excellent ride and handling even compared to the stock 215/60-14. I ran 225/50-16 for awhile and they handled well but the ride sucked.

I've got 205-55-16 Contisports. Less tire = less unsprung weight = better ride.

quote Originally posted by TK: I tossed my daughter's 205/55/16 Michelins on my Fiero for about a month. That has been the best combo hands down. Excellent ride and handling even compared to the stock 215/60-14. I ran 225/50-16 for awhile and they handled well but the ride sucked.