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How to measure tread depth with spare change

Checking tire tread depth and wear with a penny on Lincoln's head

Your tires are, without a doubt, one of the most crucial safety features of your car. Your tire tread is the depth of the ridges on your tire. As you drive and your tires contact the road or the ground, the tread gets worn. Once this happens, your wheels will lose the necessary traction to get you around safely. In combination with wet road conditions (rain or snow), worn treads can lead to hazardous consequences. Once tread depth reaches 2/32nd of an inch or less, you must discard your tires for new ones.

So, how do you measure such a small measurement? Quite frankly, a measuring ruler is not going to cut it. A tread depth gauge is a preferable tool to measure your tread depth, but not everyone has this. If you’re in a pinch to test your tires, you can use a penny or quarter to do the trick. Here’s how:

The Penny Test

Grab a penny and point Honest Abe’s head down towards one of the open crests in the tire. Insert the penny and look closely at where Lincoln’s head is situated. If his head is no longer apparent, then your tires are still in good condition. If you can see all of Lincoln’s head, your treads are overworn, and you’ll need your tires replaced ASAP.

The Quarter Test

If you don’t have a penny on hand, how about a quarter? It’s the same steps: PlaceWashington’s head down into a ridge. From the edge of a quarter to the top of Washington’s head, the length is about 4/32nd inch (instead of 2/32nd inch with a penny). If the tires don’t touch Washington’s head at all, then it’s a warning you need new tires.

The Penny Test has always been a trusted trick for vehicle owners, but it’s okay to use a quarter instead. Some even argue that the Quarter Test is better as it can give you a better idea of when to replace your tires as anything less than 2/32nd of an inch is considered dangerously low and illegal. In other words, the Quarter Test gives you a little more wiggle room. 

For all your automotive needs, we invite you to come by John’s Auto Care. Our experienced team has many skills, from tire rotations, tire replacements, wheel alignments and more.