Tires: Tire vibration, pirelli scorpion str, michelin ltx m s

Question
Barry,

John mentioned that my question was "outside of my expertise" and therefore could not provide any answer. Is this something you might be able to help with?

I have a 2008 Ford Expedition EL and just replaced the original Pirelli Scorpion
STR shoes size 275/55 R20 with the Michelin LTX M/S size 275/55 R20. The OEM
shoes didn't perform real well in rain and snow. After getting the Michelins I
discovered on a long road trip that at speeds above 70 mph there is considerable
vibration in the steering wheel. It is significant enough to actually see the
wheel vibrating and when I decreased the speed below 70 it would stop. Could
there be a manufacturing problem with the tires or would this be an install
issue?

Thanks for the help.


Answer
T,

There are a number of possibilities and tires is only one of them.

First, rotate the tires and see if the vibration moves from the steering wheel to the seat back.  If it does not, then the problem is in the vehicle itself and not the tires.

If it does, then it is some sort of wheel end problem.  It could be concentric mounting, the rim, or the tires.  And diagnosing those will require some work by a tire shop.