The Penny Test – Checking Your Tire Tread Depth

Nothing has a bigger impact on your car than the tires. They affect its safety, performance, and gas mileage. But too few people remember to perform even the most basic checks to their tires.

One of the first checks you should make is a visual inspection. Look for any problems, such as tears, cuts, bubbles… anything that looks different from the other tires. These indicate serious safety issues that need to be addressed immediately by the technicians at your local Cottman center.

Checking Tread Depth With A Penny

If everything looks okay, check the tread wear. You’ve probably heard about the “penny” check, and if you’ve been wondering how to perform the penny test here’s how:

1. Take a Lincoln penny and stick it into the tire tread, with Lincoln’s head facing the tire.
2. Align your fingers with the top of the treads, and use them to mark the tire tread depth on the penny.
3. Remove the penny and check where your fingers are in relation to Lincoln’s head.

You should see some of Lincoln’s head above your fingernails. If not, the tread is worn to less than 2/32” (about 1.6mm). That means the tire’s worn out and needs to be replaced immediately.

Gauging The Tire Pressure

If everything else looks okay, check the tire pressure. Get a good pencil tire pressure gauge and take it over to your local Cottman and ask them to check it for accuracy. Once you know you have an
accurate tire pressure gauge, check the tire pressures. Always check the tire tread depth first thing in the morning when they’re cold; after you drive the car the tire will warm up and the pressure will be higher.

Compare the pressures to the specs; they’ll be listed on a sticker on the driver’s door post or glove compartment. If the pressure’s low, you can adjust it at any gas station; they should have a tire pressure pump available.

Finally, take the car for a ride. Drive slowly down the road; about 10 to 15 MPH (15–25 kph) should do it. You’re looking for any type of wobble or vibration that seems to go away when you speed up.

If you feel that type of problem, get your car over to your nearby Cottman center. They’ll check the tires for a possible shifted belt and, if they find a problem, they’ll make a recommendation for replacement.

Few things have a greater impact on your car’s safety, performance, and gas mileage than the tires. That’s why it’s a good idea to check them carefully, and do the penny test, at least once a month.