Just brought my "new to me" 99 FRC home from Detroit, 2544 miles, to Olympia, WA. Had a great trip across the top of the US on I-94. This is my first Vette and I had a great time.

Now for the subject question.....I noticed the Vette had a tendency to step out (bump steer) when one hits a bump in a corner at moderate speed to high speeds. Do all of the C5's do this? Granted the car settles quickly once it lands again. However, I am not accustomed to this happening in other sports cars that I have owned. I have experience in autocross and some limited road course time in a Miata with adjustable Konis and Ebach Pro-springs.

Any inform would be appreciated.

:p: :p:

 

If you have runflat tires, the stiff sidewall of the tires is part of the problem. Welcome to the Forum!!!!!!!!!! :seeya

 

Congrtas on the new car and welcome!!! :thumbs:

 

Bump steer is fun, keeps you awake in the curves. :smash: :lolg:

 

I know what you are talking about, and not trying to split hairs, but bump steer is the camber change as the wheel travels up or down.

 

:iagree:

 

Coil overs and/or softer tires may alleviate that problem. :)

 

BINGO!

Even the new BMW Z4, which comes factory-equipped with runflats (Bridgestone, I think), exhibits that ugly bumpsteer trait. I'm convinced that you will feel a huge improvement if you switch to non-runflats. When my tires are worn out (or maybe sooner), my runflats are history!

 

It is all about the tires. Dumped my run flats & the problem only shows up when its time to chg tires again. Weclome...

 

Sounds good. I have Toyo T1S's on my Miata and will mostlikely put these on my Vette once the run-flats are done. You are right, it does keep you involved in the corners.

:cheers:

 

Welcome to both the Forum and the world of run flat tires.

 

You might want to check and see if your car has been lowered. I just lowered my 2001 and it increased the Bump Steer quite a bit.

 

I noticed quite a reduction in this when I went from the Goodyear runflats to the Firestone runflats.

 

dump the runcraps!! :cheers: welcome to the forum :cool:

 

No, No, No; bump steer is a change in TOE as the wheels move up and down. That change in toe does exactly what a change in steering input would do.

 

Ew "K" We are talking about two different things, Bump Steer and the Rear stepping out over bumps, or hopping. First looking at Bump steer. Bump steer is actually caused by the different component geometry in the front suspension and steering system, and it is due to toe changing over bumps (not caster) The front tie rods pivot from a different distance from the spindal than do the A-Arms. They actually draw two different arcs in their travel. When you hit a bump and the suspension moves upward the different geometry between the tie rod and the A arm, cause the toe to change for that tire and the car to change direction ever so slightly. There are kits to correct this, I have one on my car. With the kit you can adjust to zero toe change over the full range of suspension travel. It is a lot of work and testing and alignment. the NASCAR guys all do bump steer to zero toe change. It also determins if your car is going to be tight in the turns or loose. Front end alignment can be some hairy stuff, every thing works on a arc and all the arcs have different center points. Not only that but when turning then another set of arcs come in to play like how much the front tires actually turn and the inside tire going a different distance that the outside.

Now for the rear stepping out, that is a whole other issue Like above some of the corrections are; loose the run craps, change the shocks, go to a lighter spring. This is just the simple fact that when the rear tires both go over a bump in the road in a turn and the bump causes the stiffer suspension and tires to hop up and centrifigal force takes over to cause the rear to step out. Not a whole lot you can do on this. Maybe coil overs, but if you are running any kind of performance suspension, you will have this to some degree. SOOOOO Pay attention, it can get fun. I know of one person a few years ago that wiped out is brand new 98 for exactly that fact. He was on an entrance ramp decided to kick it pretty good, just before merge to high speed traffic, he hit a cross the road bump, the rear kicked out and he over corrected she spun to the inside where he hit a cement wall. He was probably doing at least 60 plus. Ouch!

Jer


[Modified by BlueDragon, 10:26 AM 6/2/2003]

 

Danny, hello from W5RD

73, Roger