What do Snow and Winter Tire Ratings Mean?

When you’re trying to find the best tire for driving in winter, the many different tire classifications and ratings such as “Winter Tire”, “M+S Rated”, “3 Peak Mountain Snowflake Rated” and “All-Season”, can leave you even more confused! At TireResearch.info, we explain these ratings for you so that you’ll have confidence in choosing the best tire for winter driving safety and performance.

What does the M+S rating on a tire mean?

M+S is short for “Mud and Snow”, and the M+S symbol stamped on the sidewall of a tire indicates that the tire has better traction, braking, and handling performance in mud and snow than tires without it. To have the M+S rating, a tire must have a tread pattern surface area that is 25% grooves (the spaces between the tread blocks) to evacuate wet mud and snow, and to allow the tire to dig into muddy or snowy terrain effectively for better traction. Just as many other industries must submit their products for testing to make sure they meet consumer safety standards, the tire industry requires manufacturers to test their products and meet certain criteria before they can use the M+S Rating. 

Tire manufacturers are not required to submit their tires or tread patterns for testing to be called “All-Season”, so All-Season tires are not automatically M+S rated. How do you know if your tires have the M+S rating? Check the sidewall of your tires; you’ll see M+S stamped onto it, similar to the image below.

The M+S Rating on a tire indicates that it is suitable for winter use. Mud+Snow Rated tires perform well in packed snow and mud conditions.

Are M+S tires the same as Winter Tires or 3 Peak Mountain Snowflake Rated tires?

Not all winter tires ratings mean the same thing; There is a difference between an M+S rated tire, a tire with the 3 Peak Mountain Snowflake (3PMSF) rating, and a tire that is classified as a dedicated Winter tire. How do you know which tire will suit your needs best? Let’s dive in.

Mud + Snow Rated (M+S) Tires have a tread surface that is 25% grooves, to provide traction in mud and snow and to better evacuate water when driving on wet terrain. M+S Rated tires are considered All-Season tires, and are a great choice if you live in a climate where the temperature does not drop below around 46 °F (7 °C) in the winter. They will still provide good traction in snowy or muddy conditions, and you won’t have to go through the bother of switching to winter tires. Keep in mind that Mud + Snow Rated tires are not considered Snow or Winter tires, and if you live in mountainous areas or places where the temperatures are regularly lower than 46 °F (7 °C) or you typically get more than an inch or two of snow, there may be laws in your area requiring you to use winter or snow tires in the winter.

Winter Tires is a classification term used by the tire industry to group similar types of tires together. For this reason, if you’re trying to determine whether a tire will stand up to the harshest snow, ice, and winter conditions, you will have to rely on additional information, such as the 3-Peak Mountain Snowflake Rating.

The 3-Peak Mountain Snowflake (3PMSF) Rating sets the industry standard for snow tires. A tire that has a 3PMSF symbol stamped on the sidewall shows that the tire has been rigorously tested and meets industry standards for good performance in severe snow conditions. While an M+S Rated Tire is optimal for its versatility, for more harsher winter conditions, a 3PMSF Rated tire may be a better choice. 3PMSF tires are made of softer rubber that maintains its pliability, even in very low temperatures to maintain traction on ice and snow. They also have extra siping and tread patterns designed to dig into ice or snow for better traction. You can see the distinctive symbol of a mountain with three peaks and a snowflake, in the image to the right.


Do you need an M+S rated tire?

When deciding on what winter tire is best for your needs, consider if your state or province has laws mandating use of certain types of tires in winter or in certain regions, such as mountainous areas. Also a consideration is the severity of your winters. Does your region regularly have winters colder than 46 °F (7 °C), or get more than a few inches of snow at a time? If so, then a 3-Peak Mountain Snowflake tire would be best for you.

On the other hand, if winters in your region don’t typically drop close to freezing or lower than 46 °F (7 °C), but you need a little extra traction for rain, mud or light snow, then the M+S Rated tire would be a great option, and one that you can keep on your car year-round. 

At Tireresearch.info, our goal is to give you a better understanding of tire ratings for winter so that you can make decisions that help you feel more confident that your tire choices are protecting you on the road.