corvttdude

I have been chasing a vibration issue since I purchased the car, and while I've certainly made it better, I still have yet to track down the cause.

For reference, The car is a 2002 with about 56,000 mi on it, it's running C6 Grand sport Wheels, with hankook ventus V12 tires. It's got silvers coilovers, and a z06 rear sway bar with the metal endlinks. I replaced the crappy not hubcentric spacers in the rear with good quality hubcentric spacers, and corrected two Bent rear rims. I have checked the hubs and all four are tight and don't make noise.

At 20-30 miles an hour is like the car is driving over wavy pavement, very apparent, and then it disappears until about 60 mph and up when you get the vibration again, though at this speed it's rythmic, oscillatory. I'm open to suggestions and spitballing ideas. Could replace all four tires, see if that fixes the problem, and also could replace the wheels all together and see if that fixes it as well though I would be surprised because all four have been road force balanced.

Che70velle

If you have a local friend with a Vette, spend a Saturday putting his wheels and tires on your car and take it for a drive. Wouldn’t take a couple hours to rule that out. That’s where I’d start. Leave the spacers off for this exercise.

Bruss

Try this

jim993

What do you mean by corrected the bent front rims?

The FIRST ting I would do go to a reputable tire shop, have each wheel run on the balancer in my presence to see that the tire and wheel are round, no runout and in balance. NO runout can be accepted if you want a smooth ride.

corvttdude

I will freely admit I have no idea what runout is, however the rear rims were bent quite badly from my trip home from NY where I bought the car. I had a local (by far best around I could locate" correct this. The fronts were not bent, and have been road force balanced

oharal

Runout is essentially wobble because things aren't square/are bent. If you spun the tire and the rim appeared to wobble or move, your wheel would have runout. I think you still have a goofed up wheel and you should try as others have suggested, someone else's shoes and see if it goes away.

corvttdude

Ahhh understood. I'll give that a shot and report back. Don't have a ton of friends in the car community so will have to do some hunting to find a set to try.

jdmvette

I've read in the past that oscillating vibrations can be a hub issue

corvttdude

I've certainly checked the wheel hubs, hoping that was the issue, but mine are all tight and don't make any sounds. And for what it was worth I was kind of hoping that since the car was relatively low miles it wouldn't be hubs.

MWWarlord

I agree that you need to have all 4 wheels road forced balanced. You need to make sure that you no runout at all. I would also look at getting a good alignment done. You might also have flat spots on your tires. Good luck getting this resolved.

The Former

You bent the rims? How in hell do you even do that? Not throwing shade, just want to know.

corvttdude

WELL, I bought the car in NY and that drive to FL was heinous. The car was also lower at the time then it is now. I'm pretty certain that was when it happened. And while I've had the bent part fixed, I don't think the wheels are ever going to be smooth truly again. Some would have to show me some really high quality work on them for me to think that they would run properly again

MWWarlord

It's really not that uncommon at all (especially with C6 GS rims). All you have to do is hit a pothole. The stock C5 rims are a bit more resilient. However, even on stock rims, it's not unheard of. The C7 rims were even worse. They'll bend if you look at 'em too hard.

corvttdude

I have heard pretty good things about the C6 Grand sport cup style wheels. I'm currently trying to figure out if they ever made a set in that design that were forged.

NATV

Another possibility if there is no bent rims in play is that the tires themselves cause the oscillation feeling. I'm sure old tires that sit a lot or have flat spots can cause that.

I second the suggestion to try another set of wheels and tires if you can since that would be free. Second choice would be to have a good shop put everything on a machine to measure balancing.

The Former

Rest assured I've never had a driveline vibration at that low of a speed. It's usually highway and up. The roads pretty much suck everywhere these days. Thanks fjb.

corvttdude

Truthfully if it is the wheels I'd be stoked, at least the hunt would be over.

jim993

I bent both left side rims in 2014, on the inside, running over something in the paddock.

Vibration at speed.

My tire guy ran the wheels on his balancing machine---- UH OH! Not true - runout both left side tires and wheels.

Replaced with OEM straight rims from Ebay.

From my log:

January '14 - TRACK DAY 8, No. 69 at Laguna Seca
April - Rebuild Front Calipers, flush brakes, install speed bleeders
May - Replace four slightly bent wheels with exact same used good wheels*

Good for another eight years and 15 track days--so far.

February '21- TRACK DAY 21 at Arizona Motorsports Park, No. 76
March - HP Plus Pads on the rear
April - TRACK DAY 22 at Arizona Motorsports Park, No 76
October - TRACK DAY 23 at Arizona Motorsports Park, No 77- got by a Lambo and a McLaren 4th session!

Vetteman Jack

Moved to C5 Tech.

corvttdude

Had the car in the air last night and spun all four wheels around. Whether the tires have flat spots, broken belts in them, or the wheels still aren't true, when they rotate, you can see them rise and fall. Not sure if warped brake rotors could do that. What PSI are you guys running? Read several things saying if you inflate the tire enough, the rubber will often round out properly.
if that doesn't work, I'm thinking I'll go new tires first, and when that obviously doesn't work, new wheels. But I'll buy the tires so they fit the new wheels.