Tires: Steering Wheel Vibrates at 60+ MPH

Question
Hello! I have a 2002 Pontiac Grand-Am GT and got all four new tires from Firestone called Primewell just this past April. In June, I first started noticing the steering wheel slightly vibrating and feeling a "jump" from the tires in the front seats at only 35-45 MPH. So, I took the car back to Firestone and they balanced the tires and beaded the left front tire since it went flat for no apparent reason. But, it really didn't help much. So, just this month I took it to Meineke to have them check the tires and they said the tires were fine, but they balanced them again to be sure. They recommended that I replace the rotors, which we did, but the steering wheel still vibrates at 60+ MPH. I don't feel the "jump" in the tires like before at lower speeds tho. Any ideas as to what could still be causing this problem?

Answer
Susan,

It could be the tires are out of round.

Go back to Firestone, explain to them the problem and ask them to move the front tires to the rear - and vice versa.  The vibration should change from the steering wheel to either the floor or the seat.  If it does, then one or both of the front tires are out of round and need to be replaced - under warranty, of course.

If the vibration doesn't change, then the problem is in the vehicle - likely CV joints.

Alternatively, if the Firestone shop has a Hunter GSP97000 RoadForce balancer (ask!), then they could do a Road Force test and determine which tire or tires are out of round and replace it (them.)