Unstable ride over bumps
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Joined: Aug 2004
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Unstable ride over bumps
A couple of questions regarding changing your suspension. I just recently put a set of bilstein sports and Z06 swaybars on my 98 coupe. The car's handling has been greatly improved, and I was very impressed. However I still notice that the car feels unstable when hitting bumps in the road. It is not as bad as before, but if I hit a bump the steering wheel will jolt my hands and the car will momentarily feel unstable. On a smooth road there is no problem, but we have so many crappy roads in the area it gets annoying (especially since this is my daily driver and I notice every little thing that goes wrong with the car.) I am trying to figure out what other suspension parts might need to be replaced that could be causing this. Would springs do this? Also, I have not had an alignment since putting in the new shocks. Could this solve the problem? Anyway, I appreciate your thoughts. Thanks.
Team Owner
Joined: Sep 2003
Posts: 43,084
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From: Raleigh / Rolesville NC
An alingment will help.
With rough roads, a softer not stiffer suppension keeps the car planted on the pavement. Each time the car hits a bump the supension is unsletteld and moves the car OFF the pavement, this unbalances the weight of your car. So the feeling is what you are discribing.
Are your bilstiens ajustable??
Think of a big ol' caddy going over those same bumps, smooth as silk with a softer suppension.
The trade offs.
Good LucK
With rough roads, a softer not stiffer suppension keeps the car planted on the pavement. Each time the car hits a bump the supension is unsletteld and moves the car OFF the pavement, this unbalances the weight of your car. So the feeling is what you are discribing.
Are your bilstiens ajustable??
Think of a big ol' caddy going over those same bumps, smooth as silk with a softer suppension.
The trade offs.
Good LucK
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I have BFG G-force KDWs, 275-40 on the back, 245-40 on the front. The bilsteins are non-adjustable. If this is simply to be expected more from a stiffer ride, I can live with that. I just hate thinking that there could be something wrong with my car and I am giving up performance in anyway. It's a sickness I have that is slowly growing out of control.
Last edited by Josh98RedC5; Feb 26, 2005 at 12:34 PM.
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Burning Brakes
Joined: Jun 2004
Posts: 1,083
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From: I'm not quite middle aged and I only own one gold chain! San Jose CA
I'm wondering if this has anything to do with the tire size. One of the biggest adjustments for me coming from a Cobra to the Z06 is the way that the mongo sized Goodyears cause the car to wonder and wallow when it hits ruts and other indentations in the road service. I wonder if this is contributing to the problem you're having, particularly now that the suspension has been stiffened up. That might accentuate the tire issue on your car which might not have been as noticeable with the softer suspension you used to have.
Just my 2 cents worth of thinking...you may want a refund!
Good luck!
Just my 2 cents worth of thinking...you may want a refund!
Good luck!
Burning Brakes
Joined: Oct 2002
Posts: 797
Likes: 1
From: Sunny Earthquake Country, USA On the Left Coast (which is becoming more Right!)
Originally Posted by AU N EGL
An alingment will help.
With rough roads, a softer not stiffer suppension keeps the car planted on the pavement. Each time the car hits a bump the supension is unsletteld and moves the car OFF the pavement, this unbalances the weight of your car. So the feeling is what you are discribing.
Are your bilstiens ajustable??
Think of a big ol' caddy going over those same bumps, smooth as silk with a softer suppension.
The trade offs.
Good LucK
With rough roads, a softer not stiffer suppension keeps the car planted on the pavement. Each time the car hits a bump the supension is unsletteld and moves the car OFF the pavement, this unbalances the weight of your car. So the feeling is what you are discribing.
Are your bilstiens ajustable??
Think of a big ol' caddy going over those same bumps, smooth as silk with a softer suppension.
The trade offs.
Good LucK
Is your tire pressure 30 psi cold for starters?
Next check your suspension bushings for wear (it's a '98).
Then check your steering linkage for wear (it's a '98).
Is it lowered a lot? Bumpsteer?
Rear alignment, toe?
Goodluck,
Roy
Le Mans Master
Joined: Aug 2000
Posts: 8,762
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From: Murphy TX
I'm with AU N EGL - the more 'performance' the suspension gets this is what you'll feel. It sounds kind of normal. Don't forget at the ultimate - a race suspension is intened for SMOOOTH pavement.
Z06 is somewhere in the middle. I did Z06 sways and was happIER than stock but wasn't truly happy until I did springs too. Improved the whole car - but it is bumpy on less than perfect city streets.
I'm also with Scott on front tire sizes...the C5 HUNTS the road. A combination between slightly vague steering and wide front tires sometimes make it feel like it's steering itself...very different if you're coming from another car.
Z06 is somewhere in the middle. I did Z06 sways and was happIER than stock but wasn't truly happy until I did springs too. Improved the whole car - but it is bumpy on less than perfect city streets.
I'm also with Scott on front tire sizes...the C5 HUNTS the road. A combination between slightly vague steering and wide front tires sometimes make it feel like it's steering itself...very different if you're coming from another car.
Pro
Joined: Jun 2004
Posts: 543
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From: Detroit MI
Originally Posted by Ginzo
Sounds like the what I attribute to the Goodyear EMT's runflats. You hit a slight imperfection in the road with lateral g's and the car will skip sideways just a bit but immediately grabs.
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Originally Posted by Paras
Can you further describe the motion when you hit a bump? Does the car pitch up hard? Do the front and back feel the same?
Drifting
Joined: Oct 2003
Posts: 1,884
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From: Walnut CA
Originally Posted by Josh98RedC5
Basically, when I hit a bump it feels like it wants to skip sideways a little and then immediately grabs. The car overall feels very solid, very little lean in the corners. I don't know if this would impact the situation or not, but the guy who put in the shocks for me said that my rear spring looked like it had been hit or something (previous owner) and had splintered a little. I took a look at it and did notice the splintering, but it did not appear to be anything serious. I'd hate to have to replace the springs because they are so expensive.
If its the rear and its on a turn, this is a Corvette characteristic and not very easy to fix.
I'm not a suspension guru by any stretch of the imagination but I believe that the answers to these questions will help. It is possible that there is not enough compression dampening in your Bilsteins for the road if you live in an area with bad roads. I believe that stiffer swaybars increase increase hop on bumps.
Also, has the hop been increased or decreased since you put on the shocks and swaybars? And was the hop more wobbly before but harder now?
Race Director
Joined: Dec 2004
Posts: 13,760
Likes: 75
From: Haymarket VA
I have Bilstein Sports with Z06 sway bars on my 98 vert w/ 30k miles. It's a little stiffer than stock but not uncomfortably so. Changed to Z06 alignment specs when I installed the bars and shocks and the car feels a lot better all around. Try it.
