I have an oscillating vibration at 60 mph and above. I have rebalanced the tires several times and tried different wheels and tires with no effect. I am at a loss, I can't take trips with this shaking.

 

maybe its your brake discs being warped?

 

Could also be driveshaft/torque tube related...

 

Car completely stock? Is it speed or RPM related?

 

Look into road force measurement and correction using a Hunter GSP9700 balancer and user who understands its purpose. I went through the same 'sensation' this summer thought the worse with driveline. It was time to have the rim and tire indexed to make them 'rounder' then final balance. Rides right again.

 

Jim - I think I have a similar issue. Around 60 mph there is a 1.5 second on 2 second off vibration. Had wheels/tires balance twice with no change. They used the road force balancer mentioned earlier.


I'm going to keep an eye on this post to see other recommendations to check. Thanks.

 

Does the vibration change if you press in the clutch? Does it change any if you use a different gear?

How many miles on the car? Any recent work? (clutch/driveline related)

 

Speed related, it starts at around 55 or 60 regardless of what gear I'm.

 

Sorry, I'm not familiar with a road force balancer. How do they work? The corvette tech where I live wants to check all the bushings in the rear suspension and rear alignment. He thinks its there. Cant be the torque tube/drive shaft because It spins the same speed as the engine.(his statement)

 

Speed related. Happens at the same speed regardless of what gear. The car is stock except for exhaust and intake.

 

70,000. Was doing the same thing before I had a new clutch, pressure plate, bearing, master cylinder and slave installed. Still does the same thing. Clutch in or out still vibrates at around 60 up. Stops below 60. Regardless of gear starts at around 60.

 

Road force is created from runout of the rim, tire, and sidewall stiffness variations. The wheel can be balanced perfectly but if it is not round or sidewalls have different 'spring rates' as it rotates against the road surface then this can cause a ride disturbance.

I think that since the size of front and rear wheels differ in diameter this might lead to additional issues as harmonics come into play when you reach the resonate frequency and two harmonics begin to stack causing a high response and ride disturbance. My vehicle 'resonated' to smooth then shake while traveling the same MPH on smooth surface (around 65-70 MPH). The different 'out of round' of the wheel assemblies would sometimes shake together so I felt it then a second later shake out of phase with each other then I didn't feel it.

I have a Z51 so springs are heavier, C6 Z06 shocks, and C6 Z51 swaybars with stock thin spoke wheels and Hankook tires.

The road force balancer needs an operator who does more than use it for its balance function. The main function is it can be used to read the runout and sidewall stiffness variation of the assembly, then read the runout of the rim itself, and then inform the operator where to position the tire in relation to the rim to reduce the runout/sidewall stiffness variation that causes the assembly to react when it touches the road surface. One it is as round as it can be then correction wheel weights should be placed on the wheel in dynamic balance mode - never static unless that was the only correction needed.

If one or more assemblies have a resulting value of road force too high to reduce the disturbance at least you know which ones they are and rim and or tire replacement might be required. Basically you need a corresponding amount of rim and tire runout than can be clocked in such a fashion to reduce total runout. A 'perfect' rim can not be used to correct a tire with high runout.

There is a science to proper wheel and tire service - need the equipment and a qualified operator who does not bypass the machines functions and use it as a balancer only.

Once the wheel/tire combinations are serviced and determined to be a non issue or not then you can move on to the more complex possibilities. That is what the road force machine solved for me so I could save the time and expense of going after a driveline issue that didn't exist.

 

its either the front tires wear out from a bad ilighment (run your hand around the tires and see if there bumpy) or the bushings on your torque tube

 

Mine did exact same thing. Drove me nuts. Regular balance didn't fix it nor did road force. Installed new rotors and pads and vibration is gone. Might give it a shot.

 

I agree, sounds like warped rotors.

 

I think we've solved the problem. The vibration was in the rear only, so we checked the rear wheel bearings and there it was. The left rear wheel bearing has movement. I'll be replacing this week and will post the results, might help someone else later. Thanks to all who gave me their input and tried to solve the mystery. This forum rocks!1

 

HOZO6, Check your rear tie rod ends and wheel bearings. That appears to be what was causing mine, I'll let you know what happens when I change the bearing.

 

Couple of comments that may help someone in the future. I've bought numerous sets of Michelins, and several times the tech using a road force balancer said I had a tire out of spec, so Tirerack drop shipped another tire and the bad tire went back. Once, on a Honda Accord Michelin X ice I got one tire out of spec. Tire rack said it was borderline, they would replace it if I wanted. I said I'd try to live with it. On the front, there was no vibration, but the car was very twitchy. I had to use that tire on the rear only. Also, once was chasing an intermittent vibration. My engineer brother said sometimes when the somewhat out of balance front was in sync with the somewhat out of balance rear, it vibrated. When the out of balances were opposite, they tended to cancel each other out, so no vibration. Turned out that was correct.

 

Well it wasn't the tie rod ends or the bearings. Can a sway bar end link cause any of these vibrations? mine are both in bad condition....just grasping at straws but thought I would ask. I'm at a loss.

 

Can these rotor be turned or is it a replace only situation?