Checking Tire Tread Depth
Checking your tread is fourth part of tire maintenance.
The tire tread should be more than 1/16th inch deep across the tire. If one side is worn down more than the other you may have an alignment problem. If both sides are worn more than the middle, you probably do not have enough pressure in the tires. If the center is worn more than the sides, you have too much pressure. Any bulges in the tread or bubbles in the sidewall indicate that your tires treads may have separated and the tire is at risk to blow out.
Excessively worn tires will not grip the road surface or channel water out from under the tire properly. They are more prone to slide or hydroplane and must be replaced.