1994/ZF6

I am not sure if this is a warped brake rotor(s), out of balance tires, poor alignment, bad bearing or other issue.

Here is what it does:

1) At low speeds there are no symptoms, it drives just fine
2) At highway speeds the front end has a slight vibration, nothing too noticeable in a straight line.
3) At highway speeds going around curve the front end will shake akin to an out of balance tire
4) At speeds greater than highway speeds the front end will vibrate like an out of balance tire feels but less so than in #3
5) Braking at highway speeds causes a lot of vibration
6) Braking during a gentle turn at highway speeds vibrates even more than #5

The car has 17x9.5 wheels up front. I recycled my old rear tires to use on the front. They are 285/40/17. They have about 30% tread remaining. The guy that mounted/balanced them said it was difficult and he had to use a lot of wheights.

I replaced the brake pads at the same time. At the time I was cheap and lazy and did not have the rotor resurfaced since it did not have any grooves or noticeable damage.

I don't remember how the car drove before this since it was sitting for quite a long while. I do recall it was never completely vibration free on the highway but I don't think it was quite as bad as it is now. Ball joints and tie rods appear to be in good shape and without slop. Though the ball joints do appear original (riveted in). There are no 'noises' to indicate failing wheel bearings. I am leaning toward out of balance tires and/or warped brake rotors. I will likely pull the rotors and have them cut since that is only $20.

 

http://forums.corvetteforum.com/c4-g...e-driving.html

Usual practice is to put fronts on rear and new ones on front if only replacing two tires

 

If you're getting a vibration, pulsation in the brake pedal?, under braking its probably the rotors. I've seen rotors so warped they caused a vibration like an out of balance tire. If they are that bad you should just replace them.

 

that's what the car feels like however there is no pulsation in the brake pedal at all

 

Tires can cause all kinds of vibration at different speeds.

You may have more than one issue. Tires could be out of balance. Tires could have other uneven wear issues. Could be bad bearing but not likely. Check the torque on the lugs. Could be warped rotors.

I would start with jacking the car up and pulling/pushing on the wheels. If you get movement, suspension issues. If none, spin teh tires and look for "out of round" rotation. If none, turn the rotors.

And before any of this, check the air pressure in the tires. And then get them balanced.

 

I've gone through the usual checks by tugging and shaking the wheel/suspension. I did not notice anything loose. It all seems pretty tight. The previous owner installed new shocks within the last year. I do not know when it had its last alignment - but not since I've owned it in August 09.

I'm going to start with cutting the rotors. Its cheap and easy. If that doesn't work I may just get some new front tires for it. I'm not a big fan of the 285s up front since they do track just a bit and they are fairly worn out. The tire shop that mounted/balanced them (about a month ago) indicated they were a pain to balance since they were so worn and required a lot of wheel weights. I think a 265 tire on the 9.5" rim will be a better fit, not cause tracking and hopefully the balance on a new tire with correct the issue - but of course that is a couple hundred bucks I'd rather spend later than sooner.

Thanks for the input guys.