Tire Penny Test – Best Method To Check Tire Tread Depth

Tires are the only vehicle part that has direct contact with the road. Therefore, they should always be in good condition to prevent unsafe driving experiences. Heavily worn tires can cause handling issues and even catastrophic collisions if the tires blow out due to excessive wear.

There are several methods to check tire tread wear to prevent unforeseen circumstances. The tire penny test method is the most common and straightforward tire tread wear test. However, it only requires a penny and your time to check tire tread wear depth.

This article will explain the tire penny meaning, how to test it, how accurate it is, and present other possible methods as we progress. But first, let’s start with the tire penny method.

is the penny test for tires accurate

Tire Penny Test Explained

The United States recommends measuring tires in the 32nd of an inch. New tire tread depth is usually “11/32 or 10/32”; however, some trucks, SUVs, and winter tires have deeper tread depths than passenger cars.

According to the US Department of Transportation, you should replace your car tires once they reach 2/32. And many states in the United States agree with this. Pardon me. Some states do not only agree to this, but it is a legal requirement.

The essence of the tire penny test tread wear is to see if you have reached the minimum tire tread depth as required by law in most US states. Let’s see how to test your tread wear with this method.

Grab a penny and immerse it between the tire ribs. A rib is the raised part of the tire tread circumference. A tire tread consists of several ribs.

When immersing the penny between the tire ribs, ensure that Lincon’s head faces down into the treads. Now, look at the penny and examine if you can’t see the top of Lincon’s head. If you can’t, the tire is still okay. But if you can see the entire head, the tire tread penny test has shown the tire is excessively worn and needs replacement.

During a car tire penny test, do not only run the test on all the tires but check different areas of the tires. This will help you detect uneven tire wear. If some areas of a tire pass the 2/32 requirement and some don’t, try and replace the tire.

Every tire should wear evenly. Therefore, if some areas of the tires pass the tires penny test and others don’t, you have uneven tire wear. Uneven tire wear usually results from improper tire inflation, imbalanced wheels, misaligned wheels, or other issues. You should know your tire tread wear pattern to know when something is wrong and what could be the cause.

Read Also: Why Do New Car Tires Wear Out So Fast? – Know the Causes and Tricks to Minimize

Is the penny test for tires accurate?

The grip of your tire changes the road game. If you let your tires wear excessively, you’re putting yourself at risk. Hence, you need to maintain a good grip on the road. The tire penny test is safe and reliable because it lets you know when the tread wear is within and outside the tread wear requirements.

The space between the edge of a penny and lincoln’s head is about 1/16 or 2/32, which is the required tread wear before replacement. So, if the space between the tire ribs does not cover the top of lincoln’s head, the tire has worn beyond the 2/32 tread wear requirement.

Read: What Causes Tires To Wear On The Inside? – Explained

Other ways to Check your tire tread depth?

As reiterated above, there are other methods on how to check tire tread. These methods are tread depth gauges and tread wear indicator bars.

Tread depth gauge

A tread depth gauge should be the right option if you don’t subscribe to the tire penny test. This is a more straightforward way of checking your tire depth by using a tread depth gauge. This device comes in many models and is available in many online and local auto spare part stores. Of course, their prices differ, but the cheaper ones will work as intended.

To check the tire tread depth in mm, stick the gauge probe in the groove between the ribs, depress the probe’s shoulders, and see the reading. All tread depth gauges should be able to display results in mm and 32nd of an inch.

Tread wear indicator bars

Another way of checking tire tread depth lies in the tires. Tire manufacturers understand the need for tire replacement and, therefore, equip each tire with tire tread wear indicator to tell you when the tires need replacement.

Tire manufacturers embed the tire wear bars at exactly 2/32 on the ribs. All you need to do is inspect the tires and see if the wear indicator bars are still in place; if they are flushed off, it’s time to replace them.

tire tread wear indicator

Read Also: What Causes Tires to Wear on the Outside?

Frequently Asked Questions – FAQs

Q: How do you tell if your tires are bald with a penny?

As explained above, the space between the edge of the coin and lincoln’s head is 2/32 of an inch, and the recommended tread wear before replacement is 2/32 of an inch.

So, you can tell you have bald tire tread wear with a penny test if the tire ribs do not cover the top of lincoln’s head when you place a penny in a groove between the tire ribs. Remember to face down lincoln’s head when immersing the penny into the tread grooves.

Q: Should I replace my tires at 5 32?

5/32 is still a good tread wear depth. Therefore, the tires will maintain good traction on the road at this level. However, you will experience hydroplaning when traveling at high speed on wet pavement. Therefore, replacing your tires at 5/32 is not a waste of money if you frequently journey on wet pavement.

Q: Do I need to replace tires at 4 32?

A 4/32 tire tread percentage is still a good ride. However, you can’t say so when driving on wet pavement. Therefore, from 4/32 to 3/32, you should start planning on replacing your tires. Do not let the tire wear beyond 2/32, as it would be dangerous to drive with it.

Q: How many years do tires last?

Tentatively saying, tires have expiration dates. However, these differ from manufacturer to manufacturer. For instance, some manufacturers may give up to 80,000 miles warranty on a tire, and another manufacturer gives 30,000 miles warranty on a tire. This shows that the manufacturers do not have the same faith in the two tires.

We also explained that tires should be replaced once they wear down to 2/32 of an inch. But if you’re after how many years to replace the tire without minding the tread wear, you should check your tires every six years; if not to replace them. All tires should be replaced every ten years or once they wear down to 2/32, whichever comes first.

Q: Is 7 32 A good tread depth?

A 7/32 tread depth is pretty good. You can buy a used tire that is 6-8/32 of an inch tread wear. But if the wear goes deeper to 4-3/32, you should start thinking of replacing the tire.

By this, you can buy a used tire with 7/32 tread depth. It’ll not cause handling issues or unsafe driving conditions.

Q: How long does it take to wear 1/32 of a tire?

Tires are expected to wear down 1/32 of an inch every 5,000 to 8,000 miles. This, however, depends on the tire in question. Some tires can last two times the lifespan of another tire. Several factors, like uneven tire wear, tire cupping, and irregular tread wear pattern resulting from worn suspension components, can cause accelerated tire wear.

Regardless of the cause, as your tires wear down, the tread grooves between the ribs become shallower. This invariably prevents the tires from hugging the road perfectly.

Q: How do you check tire tread with a nickel?

If you live outside the United States, you may wonder what a nickel is. Nickel is a five-cent coin in the US. So this test is just like a penny or quarter tire tread test.

To check your tread wear with a nickel, grab a nickel or quarter and hold it with your forefinger and thumb tip with Jefferson’s head facing down. Then, put the coin into the tire grooves between the ribs. If the ribs cover the top of Thomas Jefferson’s head, the tread depth is still good. If it doesn’t, you have a worn tire that needs replacement.

Q: How do you measure tire tread without a gauge?

As mentioned above, there are other ways of measuring a tire tread depth without a gauge. For example, you can measure tread wear with the tire’s wear indicator bar or a penny.

With a penny, immerse a penny upside with Lincoln’s head facing you into the tread grooves between the tire ribs. If lincoln’s head is showing fully, you have a worn tire. And technically, you have worn tires once the tires reach the wear bar indicators, which are embedded at 2/32.

Q: Are 20-year-old tires safe?

Old tires are generally unsafe regardless of the tire tread depth. This is because old tires are less complaint and unable to conform with micro peak surfaces. However, no federal rule says when tires are too old to be safe on the road. In any case, older tires are usually common to a blowout.

Q: Are 5-year-old Tyres OK?

According to National Highway Traffic Safety Administration and some tire manufacturers, a tire is generally safe if it hasn’t reached the minimum tire tread depth until it’s up to 5-6 years old. However, some manufacturers claim that a tire can last up to 10 years. Though, they advise you to check the tread depth annually after the fifth year.

Q: What is a good tire tread depth?

Tire tread wear shows whether your tires are safe or unsafe to run on the road. Generally, any tire that is 6/32 or deeper is still good to run on the road. You can still buy 6-7/32 as good used tires. However, you should start planning on getting a new set of tires once the tread comes down to 4/32. Add, do not continue driving with a 2/32 of an inch. At this stage, the tire becomes unsafe.

Final Words

While the tire penny test is a proven way of checking your tire tread depth, do not wait until it is too late. The tire tread depth quarter or penny test is meant to show you if the tire tread is down to 2/32 – the legal limit. It, however, cannot show you when the tread depth is 3-4/32 to let you plan on getting a tire replacement.

Though the law permits driving with a tire until it’s down to 2/32, your tires can become unsafe for traveling at high speed on wet pavements and even cause hydroplaning once the tread gets to 3-4/32. Hence, it is essential to have an experienced mechanic check your tires annually from the fifth year you bought them.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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