Index
Your tires are arguably the most underappreciated safety feature on your vehicle. At any given moment, you are entirely relaying on just four patches of rubber, each roughly the size of the palm of your hand. That tiny footprint carries the weight of the car while maintaining grip when your steering, accelerating and breaking. By the end of this page you will understand how to check your tread depth, tyre pressure, the different types of tyres, tyre grip tradeoff and why all of it matters.
Check Tread depth ↗
There are a couple different ways to check your tread depth.
- Using a specially designed ruler called a “Tread Depth Gauge”.
- Using a 20p coin.
- Using the tyres built in tread wear indicators.
All of these are ways of checking your tread depth and should be done so on a semi-regular basis (a couple times a month) depending on how much you drive.
The legal minimum tread depth is 1.6mm, if you are stopped and found to have tyres that are lesson than the legal minimum you can face a fine and points on your licence. It is recommended that when your tyres are at 3mm of tread you should get them replaced as anything less than 3mm starts to negatively affect your braking distance and can make it easier to aquaplane (skid/slide).
The outer rim of a 20p coin is roughly 2mm ~ 2.5mm so if you place it into any of the tread channels you shouldn’t be able to see the rim of the coin. Remember to look at the coin from the side.
Tyre Size ↗
When looking at the sidewall of your tyre there will be allot of information, to find what tyre size you have you are looking for a three digit number / two digit number then the radius of the tyre.
Tyre Size
Markings
Tyre Pressure ↗
How do I find out what pressure my tires should to be at? Google it? No need, every car should come with an information sticker showing exactly what pressure the tyres should be. The sticker will usually be found inside the drivers door frame or in the fuel filler cap (check your cars user manual if you cant find it)
One factor in accelerated tread wear and increased fuel consumption is not having properly inflated tyres.
At first glace this sticker can look rather intimidating, lets break it down.
Starting with the left column you have the various tyre sizes. On the sticker you may notice that certain tyre sizes are grouped together, this is because they share the same tyre pressures, in the below example image we are focusing on the first group of tyre sizes.
In this next section you are
Next is the “Load Type” column, this column is telling you if the car is “unloaded” (normal day to day driving) or “loaded” (lots of passengers and luggage) the corresponding pressures.
Last but not least you have the front and rear tyre pressure, these are separated as they often require different pressures.
As an example, if you had the “205/55 R17” tyres and using it for normal day to day driving (not many passengers/luggage) your front and rear tyre pressure should be 36 psi.
Most air pumps let you switch between kPa, bar and PSI (these are just various ways of measuring pressure). Before inflating your tyres, check which unit the machine is set to use and match it with the corresponding value on the sticker.
Make sure the tyres are cold before checking the tyres pressure. Excessive air pressure makes the tyre rigid and dangerously unstable, hitting a bump or pothole can cause a sudden blowout (tyre explodes).
Tread Wear Indicators ↗
Most modern tyres will have built in tread wear indicator, these are marking or features on tyres that can give you an immediate impression on the amount of wear the tyres have gone though.
The following two images show different types of tread wear indicators that you can find on your tyres. The first is the “Bumps/Ridges”. These can be found on most tyres, you will see a series of bumps running across the tread pattern, these bumps are usually set to 2mm tall. When the tread gets to the same height as the bumps, its time to get your tyres changed. As you can see in the example image the bump is much lower than the tread height so we are all good 👍
Tread Wear
Indicator
(Bumps)
On these Michelin Crossclimate 2’s they make use of the bumps as well as tread wear holes. These holes serve the same purpose as the bumps. As the tread wears away the holes will disappear one by one. Michelin recommend to replace the tyre when only one hole is visible.
Tread Wear
Indicator
(Holes)
Tyre Age ↗
The age of the tyre does matter, rubber degrades over time, it hardens and can form cracks which can be very dangerous. So the general advice is to replace your tyres when they get to 10 years old. If your driving regularly you will find yourself replacing the tyres more frequently than that so the main concern is keeping an eye on the treed depth more than the age of the tyre. If you are buying a used car that is older than 10 years, make sure you check ALL the tyres as its not uncommon to have different tyres on the font and back. As you can see in the image below the tyre in this case was manufactured in the 51st week of 2025. (52 weeks in a year)
Age
Markings
Types of Tyres ↗
Did you know there are different types of tyres designed for different seasons/weather conditions?
Summer Tyre
All Season Tyre
- Summer tyres: Best performance in dry/wet conditions. Poor grip in snow and ice.
- Winter tyres: Specialise for cold, snowy, and icy conditions. as these tyres are designed for gripping the snow they can have an increased tread wear during summer, they are generally less fuel efficient to run in dry conditions.
- All-season tyres: A compromise between summer and winter tyres. Good performance year-round.
- Off Roading Tyres: As the name suggests, these tyres excel in offroad conditions.
Having the right tyre for the right weather is important. Summer tyres during snowy and icy conditions will have significantly less grip.
The above video was created by @tyre review
Why is tread depth important?
If you live in an area that regularly experiences snow and ice, consider using all-season tyres as a minimum – or winter tyres if conditions are frequently severe. Many drivers have two separate sets of tyres and switch them out seasonally.
When driving over water on the road, the water needs somewhere to go. Your tyre tread is designed to push that water out from under your tyres so you can maintain contact with the road. When the tread is too worn the channels that would move the water out from under the tyre are not as effective and the water will have nowhere to go, the water will then get wedged between your tyre and the road, you loose traction with the ground and subsequently “aquaplaning”.
Breaking distance is also affected by tread depth.
Make sure there is no damage, such as cuts, bulges, nails etc