There are three key questions to ask about your tires to ensure safe travel:

Are your tires aligned?
Are your tires mounted correctly?
What is proper tire rotation method?

When a tire is not properly seated on the wheel, vehicle vibration and/or irregular tire wear will result. This mismount condition is clearly visible to the naked eye as a variation in the distance from the wheel flange to the "GG ring" as the unloaded assembly rotates freely.

The GG-ring is a raised circumferential rubber ring on the tire sidewall just above the bead seating area. A tread depth gauge can often be used to measure the distance from the wheel flange to the molding mark (GG ring) on the tire. The variation in at least four measurements around the wheel should be no greater than 2/32.

Mismount often results in tread depth variation around a worn tire. The major cause of mismount is inadequate lubrication of the tire and the wheel.