Do you know the “snow platform” of studless tires? How to tell when it’s time to replace | MOBY [モビー]

In winter, we are more dependent on tire performance than in summer. The condition of studless tires in snowy and cold regions can be said to be the lifeline for safe driving during winter. However, as tires are said to be raw, even if you try to replace a stored tire, it may not be usable depending on the condition.

Studless tires require more careful checking and management than summer tires. This time, we will explain the “snow platform”, which is the point of how to distinguish between usable studless tires and unusable studless tires.

First, if the rubber becomes hard, it cannot be used.


Rubber hardens when the temperature drops. Studless tires are softer than summer tires and use rubber that does not harden even at low temperatures, so you can run without slipping even on compacted snow or ice.

However, as tires harden over time, studless tires reach the end of their service life when sufficient flexibility cannot be secured even if grooves remain. Although the lifespan varies depending on the manufacturer, brand, and storage method, it is said that around four years is the standard for rubber to harden and become unusable.

How to check the tire manufacturing year

Checking the manufacturing date of the discarded tire…

If you don’t know the period of use, check the year and week of manufacture stamped on the tire. The last 4 digits of the numbers and letters stamped on the sidewall of the tire represent the year and week of manufacture.

The last two digits of the four-digit number represent the last two digits of the year, and the first two digits represent the week of manufacture in that year. If the four-digit number is “2312”, the week of manufacture is the 23rd week of 2012, which means that the tire was manufactured 10 years ago, from late May to early June 2012. .

If the tire tread depth is 50%, it cannot be used.


Groove depth is important even for studless tires. In soft or wet snow, the deeper the grooves, the better the bite. In the case of normal tires, in order to ensure sufficient wet grip, it is stipulated that a groove depth of 1.6 mm or more should be secured, and when the wear limit is reached, a “slip sign” appears on the main groove in the center of the tire. Protrusions called are exposed on the surface.

However, in the case of studless tires, the limit of use is when the groove depth is about 50%. If it wears further, it can run on dry or wet roads, but it will not be able to function as a studless tire.

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