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Car tires need a certain thickness to maintain their tread. So how think is a car tire, and when should you be concerned about replacing a tire?

Tires are precision equipment and have specific tolerances. They are made of rubber compounds that need at least a certain thickness to do their job safely.

A car tire usually starts at around 8 to 9 millimeters – or up to 11/32 of an inch. The tread will wear down with use, and need changing before they get to 2/32. A tire tread can readily be measured with a tire tread depth gauge or a penny.

Thickness does depend on a couple of factors, including the type of car tire. We'll discuss what to look for in tread depth as well as other measurements for tires, in addition to why it is important to know the thickness of your tires.

We've done plenty of research in regards to tires and their thickness needs. We've also replaced quite a few tires and understand the worry some drivers have when it comes to tire safety.

Table of Contents

How thick is a new tire?

Most standard all-season tires start with up to 11/32 of an inch thickness. With additional weight on them and the need for more torque, some truck tires can start with more tread thickness and a more aggressive tread. These include snow tires, especially, which are commonly driven in extreme conditions.

If you wanted to know, the sidewall also has a specific thickness, though it does vary greatly based on the model of tire. You can anywhere from ¼ of an inch of rubber on the outside all the way up to just over a half inch. Speaking in fractions, that's a big difference and often there to support a larger vehicle like a truck.

How do I test my tire tread depth?

There are many ways to test tire tread depth. We'll go over a few of the more accurate efforts.

Tread depth gauge

Tread depth gauges are the most accurate way to measure a tire without going to an auto shop. Tread depth gauges are very simple devices, often with a white stick that acts as a small ruler. These are also often attached to a tire pressure gauge so you can measure your tire's PSI while you measure depth.

Put the gauge into the tread and see how deep it goes. The ruler printed on the side will give you a great indicator of how many millimeters or tens of an inch you have left. You would also be wise to measure tread depth in more than one area, especially if your vehicle's tire looks like it has cupping, uneven wear, or is driving out of alignment.


While tread depth gauges aren't exactly expensive, pennies are just one cent. This method isn't as accurate because it can't produce an actual number for tread depth, but it does effectively tell you if you have a problem. Here is the not-so-secret: take a penny and hold it upside down in the tread so that Lincoln's head is pointing down. If you can't see the top of Lincoln's hair, it's a good sign that you have sufficient tread depth. While this method can be used in a pinch, we still recommend a tread depth gauge to know how much tread you really have. Lincoln was said to be honest, but unfortunately, his copper image can't tell a real number.

Take it to a shop

While you are in the shop getting an oil change, many auto shops will check your tread depth and PSI ratings for your tires anyway. We'll admit that their motivation is definitely to sell you a new tire, but if you need it and their measurements are accurate, they aren't wrong!

How thick do my tire treads need to be?

To drive well in not perfect conditions like rain or snow, you'll want at least 4/32”. This doesn't sound like much, and honestly, it's not. At this depth, you have probably worn your tires down significantly and also risk having them erupt – or worse yet, lose their ability to accelerate or stop quickly.

In some states, you aren't legally allowed to drive on tires with less than 2/32 of an inch because you represent a danger to other drivers or yourself.

If you are an aware driver, you will probably notice issues related to having too little tread depth left. Or at least we hope you do!

How do I slow tread wear?

Some drivers think their tires wear out faster than normal. In reality, tires tend to have a warranty for their number of miles or years and any defects are covered. With that said, you might drive a bit more aggressively than the tires are designed for.

There are a couple of things you can do to ensure your tires last a while:

Slow down

Tires are worn out at high speed and during braking, as they rub the pavement hard and create heat. If you find yourself taking off hard like a jackrabbit start or stop hard at stoplights or stop signs. The answer here is simple: Accelerate and brake with less force. Sometimes you just can't, and we understand that, but in the situations you can control, be a bit tamer.

And don't do burnouts. Burnouts are terrible for treadwear and will disintegrate your tires.

Check your alignment

A poor alignment or tires that haven't been rotated in a while can also cause problems. A vehicle that is out of alignment will result in uneven wear that makes one or two tires wear down faster than others, which also gives you an odd ride. While you will have to replace the tires eventually, problems like this can extend to your suspension and leak all the way down to having an unsafe ride. In other words, check your alignment regularly. If your vehicle feels like it pulls in one direction or the steering wheel doesn't stay straight without some force at low or high speeds, you might need some alignment help.

Rotate your tires

Rotating your tires doesn't mean moving them in place. Instead, especially as it applies to two-wheel drive vehicles, it means swapping tires and having them in the drive wheel place for a while. On a two-wheel drive sedan, only two of the wheels receive the power needed to move the vehicle forward or back. This means that those tires will have additional strain while others are rolling along with the vehicle. Switching them means that the wear is overall more even.

How Thick Is A Car Tire?

About The Author

Charles Redding

Charles Redding

I've spent many years selling cars, working with auto detailers, mechanics, dealership service teams, quoting and researching car insurance, modding my own cars, and much more.

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