Jim Grant's Tech Tips

'92 Mazda MPV, Steering Wheel Vibration

Q: The moment I replaced all four original tires at Sears on my ‘92 Mazda MPV with 55k, with Pirelli tires the same size, my steering wheel started to vibrate like crazy at around 60 MPH. I took it back to Sears immediately to have the tires balanced, but it did not help. Then I took it to a reputable GOOD YEAR tire store to balance them again, no help. I then bought a new set of GOOD YEAR TIRES had them installed and balanced. I still have the same problem. I would appreciate your opinion!

A: Are you sure that the problem did not occur until the first set of new tires were installed? After the second set of tires were installed was the shake just the same? If that is the case than it is unlikely that the tires were or are the problem. Both brands of tires are not only well known, but are a good product. The odds of having 2 sets of bad tires is highly unlikely, which would lead me to believe that you have a rim, mounting hub or a driveline problem. With that, first it has to be determined if the problem is tire/rim or driveline related. If the vibration changes as the vehicle is coasting or placed in neutral at the problem speed, then it is likely there is a driveline problem. If the vibration does not change then it is likely a rim/tire or mounting problem. Most of the Mazda MPV’s in our region have aluminum wheels, which create a good set of age and human related problems associated with these rims. Tire machines are powerful units they can and will damage/bend rims if there is air pressure still in the tire when the tire bead is being separated from the rim. This type of damage is not always easily seen and if damaged in this manner, tires can never be correctly balanced, even though the balancer says they’re balanced. Also, the corrosion on the rim can cause the mounting cone of the balancer to incorrectly position the rim for balancing, resulting in a perfectly balanced, out of balance tire. If the rims are questionable there is a procedure for checking the runout or wobble of the rims. It’s likely that the solution to your problem is going to be more investigative than replacing and balancing tires.