Penny test is an inexpensive method to find out your tire tread depth. Although it does not gives you the exact value of the remaining tread in mm or inches, it is still an effective way to see if your tires have worn to the extent that they should be immediately replaced or if their tread is yet capable of offering a good traction.
Penny tire test
Tire tread is the most important feature of a tire, both in terms of traction as well as driving safety.
It is measured with a depth gauge, which provides exact measurement (millimeters or 32nd of an inch), telling you how much tread you have on your tires.
However, you can also check your tire tread with a penny or a quarter if you don’t have the equipment.
In this method, you take a penny and place it in your tire ribs with Lincoln’s head pointing downwards. The visible portion of the forehead or head indicates the extent of tread wear.
If the head is hidden in between ribs, the tread depth is fine. If the head is visible, you should replace your tires as soon as possible because the tread has gone below 2/32”.
Is the penny test for tires accurate?
This method would just indicate whether your tire’s tread depth is above or below 2/32” but it would not give you the precise figure for tread depth.
Hence, it is a useful method to find out whether your tires have a safe amount of tread on them or are wearing evenly or not.
But if you want to know the accurate value of the tire’s tread, opt for a depth gauge or visit the nearby service station.
How many 32nds is a penny?
Detachment between the penny and the top of Lincoln’s head is about 2/32”. As this is the minimum tread your tires should have, the penny test is often used to check the extent of treadwear.
Similarly, the quarter test is used to indicate 4/32” tread because that is the distance between Washington’s head and the edge of coin.
How to do the penny test correctly?
It just takes a minute or two to do the penny tire test. Following are the simple steps to do it correctly;
- Take out a penny and put it in one of the tire ribs. You should see Lincoln’s face, and its head should be pointing downward.
- Notice the area of its head covered by tread.
- If you can see the head, your tire has worn out, and not even 2/32” tread is left on it. Such tires are unsafe for driving, and it is also illegal to use a tire below 2/32’’ tread in many American states.
- If the head is covered, but you can see the forehead, your tire tread is fairly safe and reliable. However, it is partially worn and may not provide enough traction in all situations, especially over wet pavements.
- If the coin is hidden up to the nose, your tire is ok for driving.
- Check on multiple spots to ensure that your tires are wearing evenly. If the tread is ok on some points and below the limit on others, you should replace such tires because unevenly worn out tires are unsafe and do not offer sound traction.
How often should you check your tire tread?
Tire makes direct contact with the road, and with the passage of time, their tread wears down. Resultantly, the grip of the tire is reduced on the road surface.
So it is necessary to check the tire tread regularly after a week or two or at least once a month to avoid any damage due to worn out tires.
Lesser tread depth can cause various problems during driving as it increases the hydroplaning and braking time of tires during the rainy season.
The minimum safe tread depth is 1.6 mm or 2/32-inch, but to ensure safety, the tire must be replaced at a tread depth of 3 mm or 4/32-inch.
Tire treadwear indicator chart
|Tread Depth||Tire condition|
|3/32’’ to 4/32’’||Reliable|
Penny tire test vs quarter tire test
Like pennies, you can also use quarters to check the tire tread. The method is same but quarter indicates tread below 4/32’’.
- If the tread does not reach the level of Washington’s head, tread depth is below 4/32’’. Such tires would work reliably for street driving but may not provide the desired resistance against hydroplaning.
- If the tread covers its head or forehead, you have a good amount of tread on your tire.
- Penny tire test is an easy way to find out a tire’s tread.
- Put the penny inside the tire ribs, placing it upside down, and the visible portion of the face would indicate the remaining tread.
- Using tires with tread lesser than 2/ 32-inch is risky.
- You should check tire tread regularly to ensure safety and traction.
- Quarter test is also a good alternative to indicate treadwear.