What is Safe Tire Tread?

Safe Tire Tread in the United States

In general, all vehicles must have tires in proper and safe condition with a minimum tread depth of 2/32 of an inch. It is the law in most states.

Tires sold in North America must have wear bars that indicate when tires have reached a point where the tread depth is unsafe. You can find the bars at the bottom of the tread grooves around the tire. They warn you when your tires no longer meet minimum tread depth requirements.

A Simple Way of Checking Safe Tire Tread

The penny test is A simple way to check your safe tire tread depth.

Here’s how the penny test works:

Insert a penny into your tire’s tread groove with Lincoln’s head down.
If you can see all of Lincoln’s head, your tread depth is less than 2/32 of an inch, and you should replace your tires.

Safe Tire Tread on Hazardous Roads

With 2/32″ of remaining tread depth, performance on wet highways and at high speeds is significantly reduced. The threads cannot sufficiently compress water. It is best to get new tires to allow rain to escape through the tire’s grooves.

Insufficient tire depth increases the risk of hydroplaning and skidding.

To perform well on wet roads, consider replacing your tires when they reach approximately 4/32 of an inch.

Traction is virtually eliminated if your tires have 2/32″ of remaining tread depth when driving in snow. You need approximately a tread depth of 6/32 of an inch to maintain good mobility in winter conditions.

Because tread depth is crucial for traction, winter tires usually start with noticeably deeper tread depths.

Legal Requirements

Forty-two states consider 2/32 inch the minimum legal tread depth. California and Idaho consider 1/32 the minimum, and Arkansas, Montana, New Mexico, North Dakota, South Carolina, and West Virginia have no standards on tread depth.

  Learn more about tire safety at NTHSA.gov

  Learn how to handle tire blowouts

DMV Questions and Answers by State

Penny test – photo by Mark Herreid