Their wear rate and manner indicate if the tires are wearing in an even manner. If the tread wear of the two shoulders is identical, everything is correct with the tire and it is wearing evenly. However, if the tread wear is different on the two opposing shoulders, the tire is wearing in an irregular manner and the vehicle's alignment needs to be corrected. In this manner, the driver can easily monitor the tread wear rate of the tires and prevent premature wear.