I have a persistent vibration problem on my Firebird 302. It has all the symptoms of the wheels being out of balance. ie vibration through the car at 65+, (not through steering wheel). I was originally told that wheels were buckled, so I've fitted a 2nd hand set of transam wheels, and have since had them balanced 3 times by seperate garages.

Has anyone ever had a similar problem that was not caused by the tyres being out of balance? What else could it be? I havent had the prop balanced, but everything else is ok, ie no joints gone etc.

Last resort would be to buy a new set of tryres to "see if that makes a difference", but its a bit of an expensive test and would be difficult to convince my wife that it would be a good idea!

Any suggestions greatly appreciated.

Andy

First things first. Take the wheels off and rotate them front-to-back. If the vibration doesn't change, it's not in the tires/wheels.
Next, take the driveshaft loose and turn it 180 degrees and re-install. If the vibration doesn't change, it's not in the driveshaft.
Using a "steady rest" and a pointer, jack up the rear and put the pointer very near the tire. Rotate the tire and look for deflection. It's possible one of the axle flanges is bent. Repeat for the other side.
Best of luck. Please post what you find.

Jim

bad torque convert maybe.