Don’t Know Much About….Tire Treads

Many of you will be removing your snow tires this month before the State of Maine’s May 1 deadline. When you have this service performed, we may tell you that one or more of your all season radial tires have excessive wear and will not pass State of Maine Inspection standards.


What is excessive wear?

In the State of Maine, tires are considered unsafe when the tread is down to 1/16^th of an inch. 


What is tire tread?

A tire’s tread refers to the pattern of grooves on the tire.  The primary function of tire tread is to divert water from beneath the tire to improve traction and avoid hydroplaning on wet roads.  All tires sold in the United States have what are called “tread wear bars.” These are small bridges that form between tire treads.  Look at the pattern on your tire, and you’ll see the beginnings of these bars start to form between the treads.  As your tires wear, these bars will become flush (level or even) with the tire’s tread.  When that happens, it’s time to replace the tires.

How do I measure tire tread?

If you don’t have a tread depth gauge handy, you can easily check the safety of your tire tread by using the penny test.  Place a penny upside down at the thickest part of the tire (usually in the center of the tread) with President Lincoln facing you.

Replace the tires immediately if:  you can see the very top of Lincoln’s head or the copper above it.

Start thinking about replacement if:  the hair on top of Honest Abe’s head is partially visible.

Your tires are safe if:  you cannot see the hair on top of Lincoln’s head 

And the tread is in the middle of the President’s forehead.

The performance of your vehicle’s tires is critical to the safety and performance of your vehicle; we are happy to confirm the results of your penny test with a courtesy inspection of your tires in our Service Department’s drive thru at your convenience. No appointment is necessary.