What is a motorcycle tire tread depth?
A motorcycle tire's tread depth is what tells you how worn the tire is. It is measured vertically from the top of the tread to the base of its grooves.
The more a tire rolls, the more the rubber erodes. And the closer the erosion is to the base of the grooves, the less the tire performs (especially in wet conditions). For this reason, a safety threshold has been set by the legislation of each country. Above this threshold, it is considered unsafe to drive.
Where to measure your tire's tread depth?
Legally, both the shoulder wear and tread wear should be taken into consideration. If the legal or technical wear limit has been reached at one point on the tread, the tire must be replaced.
Motorcycle tire tread depth when new
Some tires have a shallow tread when new. In particular track tires that are also approved for road use.
Although the tread depth is shallower, the legal wear limit is the same as for conventional road tires.
MICHELIN Power GP, homologated for track and road usage, has a shallow tread when new.
How to check tire tread depth?
Tire wear indicators are included in the tire design, inside the treads. They give a good indication of how worn your tire is. When the wear is close to the wear indicators, it means that the tire needs to be changed.
How do I find the wear indicators on the tire?
Wear indicators are nestled in the hollows of the treads. Since they can be difficult to find, manufacturers usually carve markers into the tread.
Michelin tires, for example, have little 'Michelin Man' markings on the rubber. They are there to indicate the location of wear indicators.
1 - Identify the Michelin Man symbol
2 - Find the closest motorcycle tire wear indicator in a main groove
Other tire brands simply indicate "TWI" for "Tread Wear Indicator" on the tire to tell you where it is located.
Motorcycle tire tread depth measurement tool
There is another way to measure the wear of your tires. Simply buy a special measuring tool from a dealer. By inserting it into the grooves, you can determine the level of wear very precisely.
Michelin has developed a digital tool that combines two functions:
tire depth control
pressure control
All you have to do is place the small needle in a groove and the depth is immediately displayed in millimetres on the digital screen.
To find out the pressure of your tire, you insert the nozzle into the valve, and it is displayed in bars on the screen.
What’s the legal requirement?
All tire manufacturers include wear indicators in their tires with a height of 0.8mm. However, it is important to know that this value is indicative and allows you to know, when the wear level is approaching it, that it is time to change the tire.
It is your responsibility to ensure that the wear level of your tires never passes this legal limit.
Driving over the legal limit carries significant risks
By driving beyond this limit, you would not only be breaking the law. You would also be putting yourself at risk. When you reach this limit, your tires are less efficient because they have hardly any tread left. In rainy weather, for example, water can no longer drain away and the risk of a fall is therefore high.
Once the treads are worn away, erosion can reach the tire plies and the carcass can fail, which is a dangerous deterioration for your safety.
When to check the wear level of your tires?
We recommend that you check the wear level of your tires every time you check your tire pressure, which should be done once a month.
What causes tire wear?
It is important to differentiate between normal tire wear, which occurs over time through driving, and premature wear, which can lead to an earlier tire change.
Premature wear can sometimes be avoided in order to preserve your tires and allow you to enjoy their performance for longer.
Incorrect pressure, for example, can cause more pronounced wear on the centre of the tire (in the case of over-inflation) or on the shoulders (in the case of under-inflation) and therefore lead to an earlier tire change. Check your tire pressure once a month so that it corresponds to that recommended by the manufacturer.
Transmission, fixings or a very sporty driving can also cause premature wear. If you have any doubts, contact your local tire dealer.
