M+S vs. three-peak mountain snowflake

By: Discount Tire

Your tires in the snow: M+S vs. three-peak mountain snowflake


You know the streets in your neighborhood like the back of your hand. You’re highly attuned to the handling of your vehicle. You pride yourself on your defensive driving abilities. But when the temperature outside is starting to dip and the forecast is calling for snow, how confident will you be in the tires on your vehicle?

There are all-season and all-terrain tires, and there are additional designations to tell you what you can expect from those tires. What do they really mean and how do they stack up when the snow starts to stick?

M+S: Mud and Snow

Back in the 70s, drivers could start finding “M+S” tacked on to the end of a tire’s name (or sometimes a variant like M&S, M/S or MS). Considered suitable for “Mud and Snow” conditions, we still routinely find this on some all-terrain tires.

However, just having “M+S” in the name didn’t mean you could rely on it as a true winter tire. The original point of the designation was to decipher by the name that the tread would be of the knobby variety—a tire that you could reasonably expect would do better than a standard street tire in mud or snow just by looking at it.

In other words, there was no test to verify the level of traction performance expected with M+S. By looking at the tread design, you would see at least 25% void (the open space) and notches in the shoulder. Otherwise, it was decided by the manufacturer to include it in the name to help customers identify what kind of tire it is.

Three-peak mountain snowflake

Clearly, there was a need for a way to truly instill confidence for consumers who are concerned about traction in severely snowy conditions. In the 1990s, the U.S. Tire Manufacturers Association (USTMA) came up with a standard and it extends beyond the traction expectations of a knobby truck tire.

Without going into the measurements and mathematics, the standard outlines an acceptable minimum of traction in medium packed snow as compared to a standard tire. Tires that meet this standard have now earned the right to use the M+S designation. A popular and reliable example is the Cooper Discoverer M+S.

More importantly, tires meeting the standard can be identified with the “three-peak mountain snowflake” symbol on the sidewall. This symbol, also referred to as the “severe weather” symbol or the “Alpine” symbol, is a distinctive pictograph of a six-sided snowflake inside a mountain with three peaks.

Of course, any tire that falls in the “winter tire” category should have this symbol to prove it as a true winter tire. For all-terrain truck tires that aren’t necessarily intended for winter-only use, having the symbol becomes a badge of distinction and an added benefit to give you peace of mind in the snow. In these cases (for example, the Nitto Exo Grappler AWT) they often forego including the “M+S” in the name, even though they qualify.

What are the limits of the three-peak mountain snowflake designation?

In some ways, this standard is just the tip of the iceberg when it comes to defining expectations for tires in winter conditions.

Though the standard defines minimums for traction in severe snow conditions, it does not take into account braking or turning in snow (not to mention traction in icy conditions). So simply seeing the three-peak mountain snowflake on your sidewall isn’t a guarantee that the tire will be the optimum choice for winter conditions in your neck of the woods without adding studs to the tire (when applicable) or using of snow chains when permitted.

Get the traction you need

The technology in how tire tread patterns are designed and how their physical compositions are developed is continuously improving. There are still many differences to consider in your choices for winter tires, as reflected in their performance and price.

This is where we come in. With the right equipment, drivers have never been safer on winter streets.

We have a huge selection of winter tires and all-terrain tires branded with the three-peak mountain snowflake symbol; we surely have what you need to be safe when the snow starts to fall. If you need help deciding, visit your neighborhood Discount Tire store. Our staff knows what will work best for the conditions where you live.