vibration problem

[frltsta11]

I,ve posted this before but haven't been able to find the problem so I'm going to try again. I have a 97 c5 that starts to vibrate at 55-60 mph. It does it whether I'm coasting in neutral or not. Tires have been balanced several times and have even been replaced.
Alignment has also been done. Could the driveshaft be bent or are there any u-joints that can be going bad? How about the half-shafts? I've also replaced a couple of wheel bearings. The car runs smooth up to that mph. I need help bad on this problem it's driving me crazy.

[vettepilot]

Although it doesn't happen often, it is possible that the tires dispite several balancing jobs could still be the culprit. Sometimes one or more tires will have a vibration only at a certain RPM range(read speed).
One way to eliminate tire/wheel is to have your tech remove the rear tires and while the car is up run up through the speed range where the vibration normally occurs. If it's gone, then it is one of the following:
A.One or both rear tires/wheel combinations

B. The front tire wheel combination is the culprit

C. If you suspect B. put the front tire/wheel combination on the rear and run it up again into the vibration speed range and note if the vibration is there or not. Granted you won't leave them there to drive because of the size difference, it's just for trouble shooting purposes.

If the vibration is present with the tires removed, then you need to begin trouble shooting the drivetrain, particularly the front /rear drive shaft couplings and the half shaft joints. Bearing problems usually don't present themselves in the form of a vibration with a small speed range.

Looking at the post again, I noted that you already replaced the tires. Look for a bent rim, could be caused from over torqued lug nuts, or something that makes it "out of true".

Let us know what you find.
vettepilot

[JBsC5]

If you happen to have a friend who owns a C5 relatively local nearby..

Swap out the rims and tires one day and see if that solves the issue..

You could have hit a pothole or something and the wheels either front or rear could be the issue..

Try the fronts first ..then go back and try the rears..

Good luck..and I too would be driving myself nuts with a vibrational issue at 55 -60mph..on a car such as this..

Lots of C5 guys that have gone with aftermarket rims might even have the original set of rims and tires laying in the basement..

JB

[JBsC5]

Is your car an automatic or a stick shift..?

Has the clutch ever been replaced?

If its an automatic...is does it have an aftermarket torque convertor in it?

The reason I ask..is the driveshaft on the C5 has a certain procedure for removal and if not followed correctly..could also cause similiar problems..

I'd go after the simpliest area first..the wheels and tires..

[danl72]

Sounds like it could be the tires or wheels. I would do what JBsC5 said and swap them out and see if that helps.