I installed a set of Mickey Thompson’s street radials on my car and redid the rear now cruising at 70 plus. Get a vibration in the seat. I have had the tire balanced twice no help. change from a posi unit to a truetrac cut the axle ends off put a set of big bearing ford ends on.axle go in and out with no effort. Is this normally with these tires or is there something wrong? Any help would be appropriated.