What Does the M+S Brand Mean?

How do M+S (Mud and Snow) branded tires, All-Season tires, and three-peak mountain snowflake branded tires differ in the snow? One word; Traction! And while you may not know which tire offers the best traction in winter weather, it'll only take one slippery slide into a snowbank to pique your curiosity!

The original definition of M+S tires was based on the geometry of the tread design. The M+S designation was used to differentiate the knobby, bias ply tires intended for use on muddy and/or snow-covered roads, from the straight rib tires used on early cars or trucks. These tires were branded with the letters "M" and "S" in several different configurations; M&S, M+S, M/S, MS, etc. at the discretion of the manufacturer.

When early radial ply tires proved to deliver better snow traction than straight rib, bias ply tires, manufacturers introduced All-Season tires with a variety of tread patterns. Delivered with an unspoken promise to provide good traction in all weather conditions, All-Season tires grew in popularity. Drivers soon recognized though, that winter snow and ice traction didn't hinge on tread geometry alone.

As a result, in 1999, The U.S. Rubber Manufacturers Association (RMA) and the Rubber Association of Canada (RAC) agreed on a performance-based standard to identify passenger and light truck tires which attained a traction index equal to, or greater than 110 in comparison to a reference tire rated 100, during traction tests on packed snow as specified by the American Society for Testing and Materials. This new standard helped drivers more easily identify tires that provide a higher level of snow traction.

Tires that met the performance-based snow testing standard were branded with a mountain/snowflake symbol on the sidewall, known as the three-peak mountain snowflake or 3PMSF for short.