If you’ve ever taken your car in to get your wheels rotated or aligned, one of the first things the mechanic does is put this weird silver-measure like tube thing between the lines of your tire and then they tell you if the tread is bad or good. But while they are going on and on about how the psi levels read and stuff, you’re wondering to yourself what exactly does tread mean.

The tread refers to the rubber around the circumference of a tire, that makes contact with the road. Here is a visual aid:


All that rubber begins to wear off while you’re driving around. Why? Because your tires take a pretty good beating. Imagine all the potholes you’ve hit, or speed bumps that you’ve gone over. This will help you grasp what kind of damage your tires undergo on a day-to-day basis. This doesn’t mean that you’re a bad driver. If you aren’t aware of when your tires need to be replaced, then you could be dealing with some pretty catastrophic events, such as losing control of your vehicle while driving, or being left stranded in the middle of nowhere with no easy way to get home.

What is Acceptable Tire Tread?

First of all, in the United States, the tire tread depth is measured in 32nds of an inch. New tires normally come with 10/32″or 11/32″ tread depth. The tread on your tires should never, and I repeat, NEVER fall below 1/6th of an inch. (This translates to 1.6 millimeters for those of you the prefer decimals rather than fractions). It’s really recommended, and enforced in some states, that tires should be replaced when they 2/32″. But if you’re not in the exact mood to go down to your mechanic or dealership to get your tires checked, then there is a simple solution. It’s called THE PENNY TEST! This test determines if you’ve hit the 2/32″ threshold. Here’s how to do it:

1.) Grab a penny and put it between the tread ribs (the raised part of the tread that stretches across the circumference of your tire.) of your tire. (The tread is made up of several ribs.)

2.) Turn the penny so that Lincoln’s (The President on the penny) head is down into the tread.

3.) If the top of his head disappears between the ribs, then your tread is above 2/32″ which means you’re good! But, if you can see his entire head then it may be time to replace your tire(s) because your tread is no longer deep enough.