Tire Tread Depth: Why It Matters and How to Measure It
Posted on May 19, 2022
It doesn't matter if you're driving a classic car, a super high-tech electric vehicle, or an 18-wheeler. Safety is the number one priority for all of them; the condition of the car tires and tire tread depth plays a crucial role in this regard.
Surprisingly, tire condition is often overlooked, and many don't even know when tires are no longer safe for driving. At this point, you should measure the tire tread depth. But what is a good tire tread depth? Or what is the minimum tire tread depth in Canada?
To help you out, we've answered the top ten questions you may come across when checking your tires. First, let's see why tread depth is important.
1. Why Is Tire Tread Depth So Important?
A car's tires are what separate it from the ground.. The treads provide grip on the road as you drive. They keep the tires from becoming too slippery by channeling water away from the tires, helping you avoid accidents.
A good tire tread depth is key to maintaining traction on the road and minimizing the time it takes to bring the car to a complete stop. Tire tread depth also plays a significant role in a vehicle's comfort. If the tread depth is greater, the driver's grip on the road will be better cushioned.
2. What Are the Risks of Driving on Bald Tires?
Too often, car owners get themselves into trouble when they drive with worn tires. When tires lose tread depth, they don't have as much force to cut through the water, causing the vehicle to lose traction and making it harder to control under rainy or snowy conditions.
Bald tires also lose air pressure faster, which affects fuel economy. That means you'll have to spend more money on gas driving on tires that don't have much grip and can skid out of control at any time.
But safety is not the only issue. There is a legal minimum value for tires' tread depth in all countries and those who fall below this value face penalties and fines. For instance, anyone driving with tires with a tread depth of less than 1.6 mm will face a $1000 Canadian per tire in Ontario.
Since you can't afford to take such risks, regularly check your tread depth, especially in cold weather (according to the winter tire tread depth chart) or bad driving conditions. Even if you don't have the time or know-how, there are reliable service centers that can check tire tread depth in Canada.
While the exact conditions differ in every region, here's a general rule of thumb to know when you should change tires:
3. How Do You Know When a Tire's Tread Has Been Worn Out?
Tread wear indicators, also known as wear bars, are evenly spaced throughout the primary longitudinal grooves. They indicate how worn the tire is. A small arrow on the tire's sidewall shows the tread wear indicator, marked as "TWI."
When the indicators are at the same height as the tread level, it's time to change the tires. Some winter tire models come with specific tire wear indicators. The winter TWI is shown with a snowflake on the tire's side.
4. How to Properly Inspect a Tire?
You should inspect tires for wear and damage once a month or before long trips. You can perform the famous penny test with a Canadian nickel in three easy steps:
1. Put a penny into a tread groove. Queen Elizabeth's crown should be upside down.
2. You have a good tire tread depth if you can't see the top of the Queen's crown between the tread grooves.
3. If you can see the entire head, it's time to change the tires.
Plus, look for cuts, punctures, or cracks in the sidewalls or tread. Also, pay attention to the DOT code on the tire's sidewall, a 4-digit number. The first two digits represent the week, and the other two the year the tires were manufactured.
5. Why Do Tire Tread Patterns Matter for a Car?
Tread patterns help tires dig into the ground for improved traction, which is useful when cruising on sand, dirt, or mud. Using the right tire patterns can increase safety, improve handling and provide a comfortable driving experience in these situations.
As tread patterns play a vital role in tire handling, engineers typically design them differently based on expected functionality, weather conditions, and other factors. For instance, symmetrical patterns provide a smooth ride, improve stability, and lower resistance.
If you need high protection and improved performance on snowy roads, they will use a directional tread pattern. On wet roads, on the other hand, asymmetrical patterns provide excellent handling and stability.
6. What Is a Good Tire Tread Depth?
The tread depth level is represented in 32nds of inch increments. The average tread depth on new tires is 10/32 to 11/32 inches, about 8 or 9 millimeters. As the vehicle's mileage increases, this number will drop lower and lower.
A good tire tread depth for most conditions is usually 6/32 and higher. If the number is 4/32, that's a sign you should think about replacing your tires. If you still ignore the tire tread depth gauges and it is down to 2/32 or less, you should not be driving with those tires as it can be life-threatening on wet roads and at high speeds.
7. How to Check Your Tire Tread Depth?
If you're worried that your tires are not up-to-scratch, it's time to test them. One way to do this is the penny test described above. Put the coin upside down between the grooves. If the other band of the coin is visible between the grooves, it means the tire's tread depth is below 1.6 mm, and you should change it ASAP.
You can also use a depth gauge to check your tires. You can find these special tools at a wide range of auto parts stores and use them to quickly measure the depth of each groove. Tire tread depth gauges are highly effective if you want to stay above the legal minimum and change your tires at the right time.
8. Is Higher Tread Depth Better?
We said that more depth means more cushion between you and the road, giving you more comfort and peace of mind while driving. It will also boost the tread block movement and minimize dry braking. Of course, too much tread depth can negatively impact handling and make it harder for you to control the car.
9. Is 7/32, 8/32, 9/32, 10/32 Good Depth?
In most cases, new tires come with a 10/32 to 12/32 tread depth, and with driving, that parameter decreases until it drops below 6/32 or 5/32, which means it's time to consider replacing your tires.
If you look up a tread depth chart online, you'll see that 9/32 on the gauge means you have only lost about 12% of the tired tread depth and still have a long way to go before worrying about your tires' tread life. At 8/32, you still have 75%, meaning that the tire is barely worn and still stable. A 7/32 tire tread depth means that the tire is still safe for driving despite the partial wear.
10. Is Tire Pressure Check and Balancing Tires the Same Thing?
No, they are not. When you check tire pressure, you need to use a gauge or a checker on or off the vehicle to see how much air pressure is left in the tires. You can adjust the pressure accordingly and get the tires in the best condition possible based on the results.
When balancing the tires, you need to remove the wheel from the car and use a spin balance device to see how the wheels are spinning by putting more weight on them.
So there you have it. We tried to present a brief but thorough guide on tire tread depth to show why it matters and how to properly check it.
Of course, you may not have the time or knowledge to figure out when to change tires, and you may feel more comfortable having it done by a reliable center. At CarHub, we are proud to be a popular center providing a wide range of services, including monitoring tire tread depth in Canada.
Owen Pham has nine years of experience writing content related to technology, finance, and marketing. He is based in London and holds a Master’s degree in strategic marketing as well as certifications in content writing.