Please ensure Javascript is enabled for purposes of website accessibility
How to Measure Tire Tread Depth?

Posted by Agota Szabo on Oct 5th 2023

How to Measure Tire Tread Depth?

How to Measure Tire Tread Depth?

Posted by Agota Szabo at Priority Tire on Oct 5th 2023

Measuring tire tread with a tread gauge

Understanding tire tread depth is crucial for driving safety. The tread depth helps a tire have the proper traction, controllability, and performance. Without normal tire tread depth, the vehicle can easily end up in a ditch.

For the average driver, measuring tire tread depth will not always be on their mind. But, it is an important part of regular tire maintenance that will help you keep your vehicle on the road, without fines to pay.

The tire tread depth 2/32" is the lowest you can have on your vehicles, but what else do you need to know? Let us walk you through everything you need to know about typical tire tread depth.

What Is a Good Tire Tread Depth?

The tread depth on a new tire is usually 10-11/32" and, of course, the more tread a tire has the better. But, that does not mean that lower tread depths are all bad. Tire tread depth 8/32" is good, but anything a bit less than the full tire tread depth is acceptable.

After this, the recommended tread depth for tire replacement starts at 4/32". At this point, the tires are quickly losing their capability to provide the necessary traction, handling, or stopping distance. This can easily lead to dangerous driving conditions.

Tire Tread Depth Guide

32nds tire tread depth chart infographic

What is the Minimum Acceptable Tire Tread Depth?

The lowest tire tread depth that is still street-legal is 2/32". Right?

Well, not quite... it is a bit more complicated to answer this.

On one hand, laws determining the legal minimum tire tread depth change state by state. On the other hand, just because something is legal, doesn't mean it is safe. Legality and the actual traction tires provide are two completely different things.

So, let's look at this in a bit more detail.

Minimum Legal Tire Tread Depth

What is considered to be an illegal tire tread depth?

The majority of US states place the minimum tire tread depth acceptable by law at 2/32". But, there are exceptions.

In California and Idaho, the required tire tread depth is 1/32", while in Texas it is 3/32". However, even in Texas the 3/32" is the tire tread depth to pass inspection, not for the tires to be street-legal.

Additionally, the following states do not have tire tread depth legal limit laws: Arkansas, Montana, South Carolina, W. Virginia, New Mexico, and North Dakota. Therefore, they have no legal limit tire tread depth necessary for tires to be used.

Minimum Winter Tire Tread Depth

The necessary safe tire tread depth for snow is higher than for dry conditions. A deeper tread is necessary for tires to be able to generate traction through snow. Therefore, the minimum snow tire tread depth is 4/32".

When the tire tread depth 4/32" is reached, winter tires should be replaced. This is because at that tread depth snow tires no longer sport their detailed siping pattern and deep grooves. These tread elements are needed for safe travel on ice- and snow-covered roads.

The recommended tire tread depth for winter is at least 6/32" to ensure adequate traction.

Required Commercial Tire Tread Depth

The average new tire tread depth for commercial models is deeper. This is mainly due to their size, load durability, and working hours, and as such, their bad tire tread depth is also larger than the standard vehicle tire tread depth requirements.

The Federal Motor Carrier Safety Administration (FMCSA) requires the commercial truck tire tread depth to be at least 4/32". This tread needs to be measured in every major groove the tire tread has. However, according to the Commercial Vehicle Safety Alliance (CVSA), that number is 2/32".

Look at it this way:

Commercial Vehicle Tire Tread Depth Requirements:
  • Commercial truck tires not conforming to FMCSA's 4/32" tread depth requirement get a citation, but the truck can continue its route.
  • Commercial truck tires not conforming to CVSA's 2/32" tread depth requirement are immediately taken out of service until the issue is fixed.

Dangerous Tire Tread Depth - Worn Tire Risks

The tire replacement tread depth is considered to be 2/32", but some tires need to be changed sooner. The minimum safe tire tread depth depends on multiple factors like driving habits, road conditions, tire type, etc. To ensure your safe driving journey, avoiding driving on low tire tread depth is important.

Unfortunately, reduced tread depth is not the only issue drivers need to think about. Tires can develop irregular wear patterns, which are caused by different tire and vehicle problems. Tire wear patterns present on the footprint can actually tell you the issues you are facing.

Still, whether it is uneven wear or the worn-out depth of tire tread (when it is too low for tire tread depth for inspection), the tires will need to be changed for a new set.

tire tread depth new - braking distance

How to Check Tire Tread Depth?

Learning to check the depth of tread on tire models is a neat skill all drivers should know. There are different ways one can go about it.

Tire Tread Depth Gauge

A tread gauge is a tool to measure tire tread depth. But, checking tire tread depth with a gauge requires you to own such a tool. A car or truck tire tread depth gauge can be purchased online, and there are some cheaper options available on the market (both for manual and digital models).

To check the car tire tread depth with a gauge, the tool needs to be placed in the groove of the tire. By pushing it down, the top of the gauge will show a number, that is the remaining tread depth of the tire. A tread gauge is the most accurate tire tread depth measurement tool.

tire tread safety depth gauge

Tire Penny Test

You might have already heard about the penny tire tread test. It is a popular method to check proper tire tread depth on tires.

Don't worry, measuring tire tread depth with a penny is easy. The best part is that you only need a penny for the tire tread depth penny trick. But keep in mind that the penny tire tread depth test does not provide precise measurements. Let us walk you through the process.

How to Test Tire Tread With a Penny?

If you want a rough estimate of whether your tires are measuring the tire tread replacement depth, checking tire tread depth with a penny is a good option. Simply place the penny in the tire groove, with Abraham Lincoln's head facing down.

The tire tread depth penny check works by showing how much of Lincoln's head is covered by the tread. If the top of his head is visible, you are at the DOT minimum tire tread depth. When during the penny test, the tire tread covers Lincoln's head, the tires still have passing tire tread depth (over 2/32").

penny test tire tread

While using a penny to measure tire tread depth will not provide the correct tire tread depth, it is still better than measuring tire tread depth with a ruler.

Penny Tire Test a Different Way - Use a Quarter

An alternative, and better according to some, to the tire tread penny test is using a quarter instead of a penny. Checking the tire tread depth with a quarter basically works in the same manner as the tire treads' penny test, and it tells drivers when the tires reach 4/32" of tread.

During the tire tread depth quarter measurement, if the tread reaches Washington's head, the tire has at least 4/32". The tire tread depth with this coin is considered to be better than the penny test for tire tread, as the penny test only warns you when tires are at 2/32" (the lowest of the DOT tire tread depth regulations).

measure tire tread depth with quarter

Tire Wear Bars

Tire wear bars are also known as the tire safety tread depth measurements that are located in the tire grooves. These bars connect two ribs and stand at 2/32" inside the grooves.

Tire wear bars are a guiding tool provided by manufacturers, which help in measuring tread depth on tire models, as long as the tread depth is 2/32". When the tread reaches these wear bars, the footprint is at the recommended tire tread depth for replacement.

Tire Tread Depth Indicator

With specific tire models, you can also check your tire tread depth with the tread depth measuring technologies included in the tread area. Whether it's General Tire's Replacement Tire Monitoring technology or Nokian's Driving Safety Indicator, tire brands help you follow the depth of the tread on a tire. These two brands are not the only ones helping drivers out, there are many more.

How Often Should You Check Your Tire Tread?

Not realizing that you have reached the tire's legal tread depth is not ideal. Not only can you get fined for driving on worn-out tires, but it is also extremely dangerous.

For this reason, it is recommended to perform a tire tread depth check at least once a month. If the starting tread depth tire is 10/32" and you realize your tires are wearing way too fast, you may also unearth other issues that need to be fixed.

Therefore, taking a look at the ideal tire tread depth wear monthly is your best choice.

Uneven Tread Tire Depth - Tire Maintenance

It is recommended to change your tires at 3/32" tire tread depth. However, how quickly you reach that tread depth, will also depend on regular tire maintenance. From maintaining tire pressure levels to checking the alignment and suspension system, drivers must take care of the tires and the vehicle.

This combination will help increase the tread life. If a standard vehicle tire tread depth starts at 10/32", then depending on the tire type, you will have between 25,000 and 65,000 miles from these tires on average. However, practicing regular tire maintenance will help you make sure the numbers are on the higher end.

Once you reach the tire tread depth replacement threshold, don't forget to secure your new tires.


What Is the Tread Depth of a New Tire?

Brand-new tire tread depth is usually 10/32" of 11/32", depending on the tire brand and model. This is the standard tire tread depth for passenger car and SUV tires, as well as for some light truck tires. The tire tread depth for replacement is 2/32". Therefore these tires have around 8-9/32" of life on them.

How Long Does 4/32 Tire Tread Last?

A standard passenger tire tread depth of 4/32 will not last long. Tires are reaching the minimum tire tread depth requirement quickly. However, there is no specific timeline or mileage the tires will last for, as that depends on multiple factors. Still, start thinking about replacing your tires at this point.

How Fast Does Tire Tread Wear?

The average tire tread depth wear is about 1/32" per every 5,000-8,000 miles. Yet, it greatly depends on the tire type and the compound used during manufacturing, as softer compounds tend to wear faster. Additionally, driving conditions and habits can also accelerate tire tread wear.

How Thick are Tires?

The thickness of tires depends on different factors, but mainly on the tire type. The overall tire sidewall thickness usually varies between 0.2" and 0.4". The wider the construction is, the heavier the tire becomes. For this reason, smaller tires tend to have narrower thicknesses compared to larger ones.

Friendly Customer Support

Need help choosing the right tires for your vehicle?


Our team of highly trained experts has the knowledge and passion to help.
Just pick up the phone and give us a ring. Or let's talk via live chat.

Our team of highly trained experts has the knowledge and passion to help.

8am - 6pm MOnday - Saturday
Closed Sunday