How to Check Tire Tread with a Penny

Co-authored by Howard Fleischmann and Eric McClure

Last Updated: October 7, 2021 References Approved

The penny test is an easy way to check the tread on your vehicle’s tires. Proper tread allows your vehicle to gain traction and wick water away the tires. If your tread is worn down, your vehicle is more likely to slide around in the rain and get stuck in the snow or mud. Your tires are also more likely to burst if you drive on weathered tread, which can lead to a crash. While the penny test will let you know if your tread is dangerously low, you may be better off doing this test with a quarter if you want to be more proactive about replacing your tires—especially if you live in an area that gets a lot of rain.^{[1]
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Part 1

Part 1 of 2:

Performing the Test

1
Do the penny test every month to make sure your tires are safe. Your tread wears down as you drive, so checking it every month is key to staying safe on the road. This test involves sliding a penny in between the tread on your tires to measure how worn down your tires are. By holding Abraham Lincoln’s portrait towards the hubcap and checking how high the rubber reaches on the coin, you can tell if your tires need to be replaced. Monitor the tread using the penny test to make sure your tread doesn’t get dangerously low.^{[2]
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- The ideal tread for most tires is around ¹⁰⁄₃₂ inch (0.79 cm), which is roughly the distance from the top edge of a penny to Abraham Lincoln’s eyes when he’s right-side up.
- The distance between the top of Lincoln’s hair and the top edge of the coin is ²⁄₃₂ in (0.16 cm), which is when you need to replace your tires.
- In the United States, tire tread is typically measured in 32nds of an inch.
2
Grab a clean penny to perform the test on your tires. Dig around in your wallet, purse, or coin jar for a clean, shiny penny. If the penny is too dirty, it may be hard to get an accurate measurement with your coin.^{[3]
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Variation: If you live in a rainy area, drive a vehicle with larger tires, or you want to be more proactive when it comes to replacing your tires, grab a quarter instead of a penny. On a quarter, the distance between the top of George Washington’s hair and the tip of the quarter is ⁴⁄₃₂ in (0.32 cm), which gives you an extra ²⁄₃₂ in (0.16 cm) of breathing room.^{[4]
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3
Rotate the penny so Abe’s head is pointing at the tire. You can start on any tire you’d like. Turn the penny in your hand so that Abraham Lincoln’s portrait is facing you and his hair is pointing down at the center of the tire.^{[5]
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- If you’re using a quarter, do the same thing with George Washington’s face.
4
Slide the penny in between the tread to measure it. The tread is the widest groove in the middle of your tire. It wraps around your tire, parallel to the sides of the rubber, and your vehicle likely has multiple treads. Choose any tread to start with and slide the penny in between it so the edge of the coin rests directly against the space between the tread.^{[6]
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- Keep Abe Lincoln’s hair pointing towards the center of the tire.
- It doesn’t matter if you do this on the side or top of the tire. Just choose an area where you’ll be able to see the penny.
5
See how high the rubber gets on Abraham Lincoln’s portrait. Note the location where the rubber that sticks up past the side of the penny sits in relation to Abe’s portrait. This will give you a general estimate of how worn down your tread is.^{[7]
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6
Check the tread on other portions of the same tire. Once you’ve noted where the rubber meets the coin, pull the coin out of the tread. Then, repeat this process on 2-3 other lengths of tread on the same tire. Finish the tire by repeating this process 2-3 times on the other sides of the same tire to find any inconsistencies.^{[8]
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- Each time you check another portion of the tire, rotate the coin so that Abraham Lincoln’s hair is always pointing towards the center of the rim.
7
Repeat the penny test on your other tires to make sure they’re safe. Once you’ve finished checking your first tire, work your way around the vehicle and check the other 3 tires. Repeat the entire process by sliding the penny in between the tread on different portions of the rubber.^{[9]
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- If you’ve never had a tire replaced, the tread should be identical on all 4 of your tires. However, if you’ve had your rear tires replaced or you had a single tire replaced after a blowout, the tread may be different.

Part 2

Part 2 of 2:

Interpreting the Results

1
Purchase new tires if you can see the top of Lincoln’s head. If at point during your inspection you can see the top of Abraham Lincoln’s hair when the penny is in the tread, your tires need to be replaced. Drive your vehicle to the mechanic or auto shop on a day when there’s no rain and at a time when there’s very little traffic. Drive slowly and take it easy. At the shop, pay to have your tires replaced.^{[10]
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- For uniformity reasons, it’s best to replace all of your tires at the same time if you can. This will avoid uneven wear and tear on your vehicle.
- If you’re using a quarter, get your tires replaced when you can see the top of George Washington’s hair. This is roughly ⁴⁄₃₂ in (0.32 cm), but the goal of using a quarter is to replace the tires before the tread becomes dangerously low.
2
Continue driving on your tires if Lincoln’s hair is completely obscured. If your penny goes deep enough into the tread that the rubber meets Lincoln’s eyes and his hair is covered by the rubber, you’re good to go. Your tires still have life in them and you can continue driving safely.^{[11]
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- When the penny is right-side up, Lincoln’s eyes are roughly ¹⁰⁄₃₂ in (0.79 cm) from the top edge of the coin.
- For the quarter test, so long as the rubber meets George Washington’s forehead, you’re good. This is roughly ¹²⁄₃₂ in (0.95 cm).
3
Get an alignment if the tread is different on one or more of the tires. If you noticed that Lincoln’s portrait was meeting the rubber at different locations on one or more of your tires, it means that your tires aren’t wearing out evenly. This is usually a sign of an alignment issue, but you must have a mechanic take a closer look. Drive your vehicle over to your mechanic and explain the problem.^{[12]
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- If your vehicle needs a realignment, it’s no big deal. This often costs $50-100 and can be done in under 2 hours if the mechanic isn’t busy. Unfortunately, this isn’t a repair you can make from home since it requires an alignment rack.
4
Replace your tires every 6-10 years, even if the tread appears fine. While the tread is generally a good indicator of your tire’s health, the rubber breaks down over time on its own. Read your vehicle’s instruction manual to see how often you need to replace the tires. On most vehicles, it’s either every 6 or 10 years.^{[13]
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Expert Source

Howard Fleischmann
Automotive Tire & Repair Specialist
Expert Interview. 4 June 2021.} If your tires are past their expiration date, replace them even if the tread looks fine.^{[14]
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Tip: If you aren’t sure how old your tires are but they were made after 2000, look for a string of embossed letters and numbers printed directly on the tire. Then, inspect the last 4 numbers in this row. The first 2 digits are the week and the last 2 digits are the year that your tire was manufactured. For example, if your tire has “2415,” it was made on the 24th week of 2015.^{[15]
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Community Q&A

Question

What is the actual dimension for the tread?

Community Answer

Your tread shouldn't be less than 1/16 of an inch in the grooves.

Warnings

Do not drive in the rain if your tread is less than ²⁄₃₂ in (0.16 cm). This is extremely dangerous since your vehicle will be very likely to hydroplane.^{[17]
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Consumer Reports
Nonprofit organization dedicated to consumer advocacy and product testing
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In many countries and most US states, driving with a tire tread under ²⁄₃₂ in (0.16 cm) is illegal.^{[18]
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PubMed Central
Journal archive from the U.S. National Institutes of Health
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