Steering wheel vibration

Hello out there! I have a '92 corvette convertible and recently had 2 new rear tires put on. Now at certain speeds I get a vibration in the steering wheel which was not there before the new rear tires. I took it to a tire shop and they said a ball joint and a tie rod end were bad. So I took it to the mechanic I use (who was the one who put the rear tires on in the first place) he put it up on the rack, drove it and said all the ball joints are fine, everything in the front end is fine,shocks tie rod ends, etc. They don’t notice any problem with the steering when they drive it, same goes for my husband. I know the car, I drive it, and it drove smooth before, so what do I do now? I don’t like driving it like this. Could only replacing the rear tires have something to do with it? Or could my front tires have gotten out of balance somehow? Also I don’t know if this is relevant info, but about 3 weeks ago, (this is after the new rears were on)I told my husband the car was making a funny noise and not starting right. He drives it and , of course, says it’s fine. I drive it the next day and the alternator belt breaks, smacking against the inside of the hood,(lovely sound) and the car has to be towed. It was pulled onto a flat bed and the driver pulled straps throught the left side tires and tightened it to the trailer bed. Could this have any bearing on my steering issue? Thanks for any help anyone can offer!

bethonalark,

Is it possible that a front left inside or outside wheel balance weight was knocked off by the flat bed driver when he put a strap through the wheel?

Is the front wheel/tire size the same as the rear?
You could try swapping front wheel/tire assemblies with the rear, if they are the same size, and see if it is better or moves the vibration to the rear(more of a jiggling seat feeling).

I agree that the balance of your front tires is the first thing to check. Occasionally, a wheel can lose a balancing weight, and since the tow truck driver did wrap straps through the wheels, the loss of a balancing weight is a definite possibility.

Years ago I put 2 new tires on an 86 Dodge Colt. The tire were marked the same size as the originals, but were from another tire maker. The car would start shaking around 40-45 mph with the new tires. I didn’t measure them, but the new tires appeared to have a larger diameter than the old ones even taking into consideration the tread wear on the old tires. I ended up getting 4 new tires for the car and that fixed the problem.

On the other hand I had a 98 Windstar that had mismatched tires with no driveability problems. In this case all the tires were Good Year. I’m guessing that different tire makers have different ways of sizing their tires. For this reason I try to replace all 4 tires at a time and from the same manufacturer.

A Corvette with low profile tires would be very sensitive to mismatched tires and tire balance. I had an 86 Camaro with 245/50-R15 Good Year Eagle VRs (Corvettes of the same vintage used 255/50-R15 Eagles IIRC) and it was very sensitive to tire balance.

If everything else checks out, you may want to consider getting two more new tires to match the rear ones.

Good luck,

Ed B.

You did not mention at what speeds this vibration occurs. That may give us some more insight into the problem. I am going to guess this is a “high speed” issue. If the tires have been rebalanced and the problem has not gone away then you may want to progress to “high speed balancing” or “road force balancing”. The former will detect balance issues that only occur at high speeds and cannot be detected by normal tire balancers and the latter will check for tire shape and uniformity as well as balance.

If this is a “low speed” issue (under 35 mph) then you can safely ignore me.