how to do a tire tread penny test

How to Do a Tire Tread Penny Test and Quarter Test: Complete Guide 2023

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If you drive a car, you are most probably familiar with the concept of tire tread. But do you know how to tell whether it’s worn thin?

Tire tread has an impact on both the performance and safety of your vehicle. Fortunately, there is a simple technique to inspect your tires with only a few pennies. Tires and their tread may be readily examined in just a few seconds thanks to a clever, commonly used penny test.

Here I will explain how to perform a penny test to check the tire depth. I will also guide you through the steps of a quarter test, an alternative to the penny test.

Why is Penny Test performed?

If you own a car, you’re undoubtedly aware of simple inspection and maintenance checks that may enhance your vehicle’s performance with no appointment with the mechanic. The condition of your tires is a significant emphasis on routine maintenance, which might involve controlling tire pressure, learning how to recognize or repair a flat tire, and evaluating if it’s time to purchase new tires.

A new automobile tire typically has a tread depth of 10⁄32 or 11⁄32 inches, but a light truck tire has a tread depth of 11/32 to 19/32 inches. When the tread nears that depth, multiple states mandate that the tire be changed. The United States Department of Transportation advises replacing your tires after they have worn down to 2/32 inches.

How, then, do you tell when your tires have reached the end of their useful life? Anyone can assess tread depth even if you’re not comfortable repairing a flat or checking tire pressure on their own. You can use a tread depth gauge or have your vehicle inspected by a professional. The simplest method, though, is to do a penny test.

How to Conduct the Penny Test?

penny test

The penny tread test is straightforward and is based on a regularly used tire tread measurement to diagnose worn tires. According to conventional belief, tire treads should be at least 2/32nds of an inch deep in excellent driving conditions. 2/32nds is also the distance between the top of President Lincoln’s head and the edge of a US cent.

  1. To examine tire tread using a penny, insert the edge of the penny between the treads of your tire. Make sure President Lincoln’s head is towards the tire. Look from the side to check if the top of President Lincoln’s head is visible while the coin is between the treads.
  2. If the top of his head isn’t visible, your tire tread is greater than 2/32nds of an inch. This means your tires are still in good condition, and you may be able to travel longer on your tires before replacing them.
  3. If you can see his entire head, your tread is worn to 2/32 inch or less and may be dangerous to drive on. At this stage, tire experts advise you to contact a tire shop and replace your old tires with a new pair.

To summarise, if you check your tires with a penny and see the top of Lincoln’s head, you need to look for new tires. Next, try the quarter test.

Using the Quarter Tire Test

The penny tread test has long been used to quickly measure tire tread and assess the condition of your tires. However, tire experts have recently warned that this test has a flaw: by the time you examine tires with a penny and find that the tread depth is less than 2/32nds of an inch, you’re already driving on slick tires that pose a safety concern.

This is certainly relevant when the weather is terrible and the road conditions are poor. The quarter test has emerged as an apt alternative to the penny test to deal with this issue.

This test is carried out in the same manner as a penny. The difference in this test is that the top of President Washington’s head on the quarter coin is roughly 4/32nds of an inch from the coin’s edge—double the distance of a penny.

  1. To compare the height of the treads to the head of President Washington on the US quarter, push the edge of a quarter into the tire tread.
  2. With this measurement, drivers may inspect their tread and find depths less than 4/32nds of an inch, indicating that a tire replacement is needed soon.
  3. Even if the tread depth goes below 4/32nds of an inch, tires still provide a reasonable amount of safety and reliability, which means you aren’t in urgent danger of damaging your car on worn tires.

The Importance of a Penny Test for Tire Tread

tire tread

Both the penny tire test and the quarter tire test are based on the idea of measuring tire tread depth to determine tire performance. While other aspects contribute to a tire’s overall performance, such as internal tire pressure or sidewall cracks, tread directly corresponds to your vehicle’s ability to obtain and keep a grip on the road. This is especially crucial to inspect when there is rain, snow, ice, or even loose gravel.

Unlike tire pressure, the depth of tire treads cannot be adjusted during the life of the tire. These treads wear away with use, and as the tires smooth out, the chance of slipping on highway surfaces increases. As a result, drivers should be mindful of the number of kilometers traveled on their tires and their wear and tear.

Simple tire coin tests give an easy way to monitor tire tread depth at home and may be performed as frequently as needed to prevent those terrible circumstances.

Hazards of Driving on Worn-out Tires

Though tires are deemed bald at 2/32 inches, they start to lose a few of their performance characteristics before that.

As the tire tread fades, it loses its ability to channel water, increasing the danger of hydroplaning, especially at higher speeds. If you know your tires are partially worn, allow for extra stopping distance in rainy circumstances.

Grip loss is an issue on snowy or icy roads. As the rubber wears, the sipes diminish, and the tread blocks lose their traction. Allow for greater stopping space, and consider upgrading your tires to keep them safe throughout the winter.

Tires with partially worn treads are more prone to punctures and loss of air pressure. And punctures may lead to a tire blowout, which is especially dangerous at high speeds since it can cause you to lose control of your car.

Final Words

A penny test will tell you when your tires are smooth. You can also opt for the alternative quarter tire test to check the tire depth before your tire reaches its breaking point.

But a tread depth gauge is the most reliable way to test if you’re driving in the winter or during a wet season. You can even ask an expert for help if you are struggling with it. Remember, the tire tread has a lot to do with the safety of your vehicle. Thus, you must check it yourself or get it evaluated by a specialist.

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