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PreviousTires are a huge expense for any vehicle and proper maintenance ensures you’re always driving on the safest set. Check out our comprehensive tire maintenance guide. It'll help you get the best life out of your tires, and the best bang for your auto buck.
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Read this StoryTires are one of the most commonly replaced items on your vehicle as they endure thousands of miles of high-speed revolutions on hard pavement. As they shed their tread due to everyday use, they become less effective bit by bit.
Knowing how to measure tire tread will help you determine when it’s the right time to replace your tires.
Without this basic understanding, you risk changing them too late and putting your safety at risk or changing them too early and wasting money.
Below, we'll cover how to measure tire tread and other tire-read-related topics to help you stay safe, save money, and know what to look out for when tire shopping.
Understanding the Sections of Tire TreadBefore you can correctly learn how to measure tire tread, you must first know the main sections of the tread. Your tire's tread has three main sections: the outer shoulder, contact patch, and inner shoulder. Spanning the tire's circumference are deep grooves — called channels — that separate the tread.
The outer shoulder is the outermost section of the tire and is outside of the last channel. On the opposite edge of the outer shoulder is the inner shoulder.
The contact patch is the area between the two shoulders — it’s the tire's main contact point with the road. This is the area where the tread blocks are thickest and where you measure the tire tread depth.
Determining a tire’s tread depth involves measuring from the lowest point in the channel to the top of the tread on the contact patch.
This depth is important because the channels are responsible for shuttling water and slush away from the contact patch to maximize traction. If the tread isn’t deep enough, the channels will be too shallow to move water and slush effectively, reducing traction and increasing the risk of hydroplaning on wet roads.
There are three main relatively simple ways to measure tread depth, but some are more precise than others.
Use the Built-In Tread Wear IndicatorsIf you look closely at the tire's channels, you'll notice small, raised bars that span the channels. These are tread wear indicator bars. If the tire tread wears to the point that it's even with the wear bars, your tires need replacing.
Use a QuarterA simple way to check tread depth is using the nickel or quarter test.
Hold a quarter or nickel between your thumb and forefinger and place the coin inside the channel, with the top of the figurehead’s head facing the tire. If any portion of the tread is covering the figurehead, you have a safe amount of tread remaining on the tire. If the full figurehead is exposed, it's time for new tires.
Always check your tires in several places as they don't always wear evenly and could be low in some areas.
Use a Tire Tread Depth GaugeThe most official and accurate way to check tire tread is with a tire tread depth gauge. The tread depth gauge will have a blade side that looks similar to a flat-head screwdriver and a gauge side with either a manual gauge with measurement marks on it or a digital readout. You can pick one up at any auto parts store for about $5 (manual) or $15 (digital).
Fully extend the blade side and place the blade into a channel between two tread blocks on the contact patch. Slide the gauge toward the tread until the gauge's flanges rest on the tread blocks on the contact patch.
Read the measurement on the gauge.
Repeat the measurement on several parts of the contact patch to ensure there are no low spots.
Using a gauge will give you the most accurate results and will allow you to compare your tire's tread depth to the requirements in your province.
Tread Depth RequirementsCanadian law requires a minimum 1.6 mm tread depth, but some provinces have even stricter requirements. The province-specific tread depth rules are as follows:
5 mm deepWhile the legal minimums are great, tire experts often note they aren't always the safest recommendations.
Large portions of Canada set the legal minimum tread depth at 1.6 mm. Tire Rack experts tested this minimum against 3.175 mm of tread. They found a vehicle with tires that had 1.
6 mm of tread took an extra 30.5 metres to stop from 112 km/h than the same vehicle equipped with tires that had 3.175 mm of tread.
For this reason, Tire Rack and many other automotive experts recommend new tires when your existing tires reach 3.175 mm of tread. Additionally, they recommend swapping out those snow tires at 3.96 mm.
How to Find the Best-Wearing Tire for Your BudgetMany variables come into play when shopping for a tire, but much of the research is already complete if you know what to look for.
Some shoppers simply follow the lead of the tire salesperson or mechanic who generally wants to sell the most expensive tire they can. Without a full understanding of how tires work, it’s easy to assume the priciest tire will last the longest. But this is't always the case.
A lot more goes into tire pricing than longevity. There are also special compounds that make the tire quieter, puncture resistant, or more stable in corners and braking.
If your main interest is a long-lasting tire, don't fall for a tire salesperson directing you to the higher-priced tires. Instead, focus on the Uniform Tire Quality Grade (UTQG) stamped on the sidewall. The UTQG will be a three-digit code followed by two letters.
The three digits are the treadwear rating, and the two letters are the traction and temperature rating. The higher the three-digit number, the longer the manufacturer expects the tire tread to last.
There are no exact numbers the three-digit code translates to, but understanding its meaning is simple. When determining a tire's treadwear rating, the base control tire has a 100 rating. The tire manufacturer estimates a 200 treadwear tire will last twice as long as that control tire, a 400 will last four times as long, and so on.
So, you may see a premium $150 tire may have only a 300 treadwear rating but lots of other attractive features that drive up the price. However, there could also be a $70 tire next to it with fewer features but a 700 treadwear rating.
If your focus is longevity, it's clear which is the right tire for you — although that $150 tire likely has benefits the $70 doesn’t.
Manufacturers estimate the treadwear rating by driving 11,520 km on a 640-km track. They stop every 1,280 km to check the remaining tread. They then use these measurements to the projected treadwear ratings.
How to Maximize Tire LifeBarring manufacturer defects, tires will last as long as they're supposed to, given your vehicle is in good mechanical condition and properly maintained. However, there are steps you can take to maximize the life of your tires.
Keep the Correct Tire PressureTire pressure is the first rule for maximizing tire life. Check the air pressure in your tires weekly — or every time you refuel — and compare it to the pressure requirements on the tire placard in your door frame.
The recommended pressure will generally fall somewhere between 32 and 38 PSI. Too much air pressure can cause the center of the tire to bulge, leading to excessive wear in the middle of the tire.
Too little air can cause the center to collapse, putting most of the car's weight on the outer edges, leading to excessive inner and outer wear.
As an added benefit, the correct tire pressure in a vehicle also helps with fuel economy.
Never fill your tires to the maximum PSI listed on the tire unless this is the pressure listed on the tire placard.
Adjust to the Driving ConditionsSlippery driving conditions, like rain- or snow-slicked streets can lead to wheel-slip, which creates excess heat and wears out tires quickly. Always adjust your driving style to road conditions. You’ll avoid spinning the tires and prolong their life.
Get Frequent Tire Rotation and AlignmentsTires rarely sit perpendicular to the road. Most manufacturers engineer the suspension system so the tires sit at a slight inward angle. This angle allows the tire and suspension to flex outward as you go around corners, so more of the tire's contact patch touches the road.
This means as you're driving straight, most of the car's weight rides on the inner portion of the tire. Rotating the tires in the manufacturer's specified intervals puts the tire in a different position on the vehicle, slightly changing its angle to prevent uneven tire wear.
Over time, all the flexing in the suspension and bumps in the road can throw off the angles. When a mechanic performs an alignment, they reset the angles so the tires are in the position the manufacturer recommends, ensuring they wear evenly.
Quality Vehicles With Quality Tires at ClutchTires are far and away one of the most critical parts of automotive safety, so it’s important to make sure you maintain them properly. This maintenance goes beyond just rotating them and keeping the pressure within specifications. You must also monitor your tread depth to ensure there is enough to provide you with the traction you need.
Fortunately, there are several ways to measure tire tread, and some require no tools at all.
All you need is good vision and maybe a coin. However, if you want to be 100% certain you’re legal and safe, shelling out $5-$15 for a tread depth gauge will help.
All our preowned vehicles at Clutch have been through a 210-point inspection, including the tires. Any tires that have less than 4mm of tread depth are replaced with quality new tires, giving you peace of mind.
Plus, all vehicles purchased online come with a 10-day no-risk guarantee that allows you to return the vehicle for a full refund within 10 days of receiving it. Beyond that, all Clutch vehicles come with a 90-day or 6,000 km limited warranty.
Finally, our car-buying experience is 100% online and free from any high-pressure sales tactics of most used car dealerships. Check out our range of available vehicles and shop from the convenience of your home.
It doesn't matter if it's summer, winter or all-season tires: tread depth is extremely important.
To confirm this statement and determine what the minimum tread depth is, ADAC experts tested winter tires in size 185/60 R14 in new condition and with different tread depths.
It is a well-known standard that the minimum tread depth for passenger car tires in Europe is set at 1.6 mm to ensure road safety. nine0003
But ADAC's extensive testing has proven that the legally defined profile depth limit only describes a margin of safety. For summer tires, the profile must have a depth of at least three millimeters, and at least four millimeters for winter and all-season tires. Less depth will be critical on wet roads, snow or slush.
The legal situation is clear: when your car tires (usually eight to nine millimeters tread depth when purchased) have worn down to the minimum allowable mark of 1.6 mm, they become more unusable and must be replaced. nine0003
However, in some European countries, such as Austria, winter tires with a tread depth of less than four millimeters are considered summer tires and are even allowed to be driven on certain routes in winter.
Check the tire tread depth several times a year for your own safety, and remember that the minimum tread depth of 1.6 mm is strictly legal. For safe driving, tires should be changed from a tread depth of 3 or 4 mm. nine0003
In order to find out what effect a small tire tread depth has on tire performance, the ADAC test team tested 185/60 R14 winter tires in new condition (profile depth of about 8 mm), as well as worn with 7.5 and 4 mm tread depth.
On snow, the differences between new and used tires were most pronounced. The braking distance of tires with a profile depth of 4 mm was already 3.2 meters longer at a speed of 30 km/h than with new tires. nine0003
Even more dramatic were the differences in traction when the tires needed good grip at launch or on inclines. The traction force depends on the depth of the sipes: the tread grooves "capture" loose snow, and the edges of the sipes adhere to a harder surface.
Here, even the 7.5 mm residual tread option can only gain 60% of the traction compared to the new tire, notes a Shina.Guide technician. Tires with a tread depth of 4 mm do not even reach half the result of new winter tires. What can we say about tires with a legally fixed minimum tread depth of 1.6 mm, which simply have nothing to row snow with. nine0003
During the test, the ADAC testers tried, among other things, to evaluate the traction of summer tires on snow, but the most they could show was a quarter of the traction of a new winter tire and more than 7.5 meters of additional braking distance at a speed of 30 km/h .
On wet pavement, it is important to avoid sudden hydroplaning, which means that tires with longitudinal grooves and sipes should absorb and displace as much water as possible.
Tires worn down to 4 mm begin to “float” on the water already at a speed of 63 km/h, while new winter tires do not until the moment when the speedometer needle reaches 87 km/h.
nine0003
In braking performance from 80 km/h on wet road surfaces, tires with a profile depth of 4 mm lose 7% of the braking distance to the new ones.
The difference in stopping distance between new and worn winter tires on dry pavement is also present. But the advantage in this matter is on the side of tires with a small residual tread depth. The reason is simple: flattened tread blocks deform less during braking, so more of the tread is in contact with the asphalt. However, dry roads are hardly a common occurrence even in countries with mild winter climates, and it turns out that in practice there are no advantages! nine0003
Testing with winter tires proves the enormous effect tread depth has on winter tire performance. And this also applies to summer and all-season tires. If you want to be safe, you should change the tires on your car no later than the moment when the minimum tread depth reaches three or four millimeters .
A warning to all motorists: using winter tires in summer is a bad idea. Due to the peculiarities of the tread pattern and the rubber compound, their braking distance is much longer compared to summer tires. nine0003
Tire wear in the United States is checked using a coin with the image of the first president of the country. A one-dollar coin is inserted into the groove of the tread with Washington's head down. If Washington's hair is visible, then it's time to buy new tires. A coin with a face value of 1 cent will also help to check the wear of automobile rubber. If the top of the Lincoln is visible, then the tires have reached the tire wear rate and must be replaced immediately.
Tire wear can also be determined with a 1 euro coin. It must be inserted into that part of the tire where the tread is most worn. If the golden circle is in rubber, then the tire will still serve you. If the gold part of the coin is completely visible, then it's time to change the shoes of your car.
Tire wear can also be determined using Russian money. The domestic 2-ruble coin must be inserted into the protector with the eagle's head down. If the top of the bird is visible above the surface of the tire, then the tire has not yet reached the end of its life. nine0059
Premature tire wear can be avoided. According to the Research Institute of the Tire Industry (NIIShP), the "life" of half of the tires is reduced due to improper operation. After all, the service life of rubber largely depends on driving style, road conditions, compliance with the load index and correct tire pressure. Therefore, it is not surprising that with the same model of car and “shoes”, the mileage of their tires can differ by several thousand kilometers. nine0059
The main causes affecting premature tire wear
For new tires, the break-in process is important.
The first 200-300 kilometers of newly purchased tires should be extremely careful, especially in winter or in rainy weather. This is due to the fact that before vulcanization, the treads of new tires are covered with a separating layer, which should be erased only during operation. Therefore, all types of rubber must be run-in. nine0003
Tire wear occurs in a variety of ways:
Uneven tire wear is normal because the tire is subjected to uneven loads while driving.
In this case, a new wheel balancing will help. In most cases, when sawtooth teeth form on the transverse grooves of the profile, it is necessary to use cruciform wheel balancing. But this will only help with the correct geometry of the axis. This will change the direction of the tire. The sawtooth teeth will gradually disappear, along with them the noise will also disappear. nine0003
If wheels with asymmetric tread patterns are changed regularly every 10,000 km, uneven wear of all tires can be avoided. But the replacement must be done on one side. That is, the front right wheel should only change to the rear right, and vice versa.
In 1992, a uniform wear rate for summer tires was established in Europe - the minimum profile depth for tires for cars, trucks and motorcycles is 1.6 mm. This requirement also applies in Russia. An exception to the rule are light wheels with a minimum tread height of 1 mm. But for wide-profile and summer tires, this rate is too small.
With such a profile depth on a wet road, the tire will have poor handling. For safety reasons, summer tires should be changed already when the remaining profile depth reaches 2 mm (wide profile - 3 mm). Modern winter tires have a tread depth of 9, depending on the manufacturer.-12 mm. Permissible wear for them is 4-6 mm.
Many modern tires have built-in wear indicators in the form of small rubber pimples. They are soldered into the base of the protector. When the tire wears down to acceptable limits, the pimples become flush with the tread. This means it's time to change the tire.
In addition, the American tire marking uses the TWI (Tread Wear Indication) tread wear indicator. Sometimes it is indicated by arrows. The tire wear indicator is located evenly in 6-8 places around the perimeter of the tire. nine0059
Over time, the life of the tire decreases, and at the same time, the percentage of wear increases. If the bead is damaged during installation, the percentage of wear increases to 10%.
