Thanks for pointing that out about the LTX MS Defender, I wasn't aware of the recently new rating for winter traction tires. It kept me up half the night reading. I don't know if the previous Michelin LTX M/S 2 would have qualified but I've run 5 or 6 sets of them on my Tundra and they have performed really well in most all road conditions. I bought a new set of the LTX MS Defenders last month so I'll be interested to see if they perform differently. Tire manufacturers are forever changing tire compounds and tread designs. Keeping up is like shopping for mattresses. Apparently Michelin is focusing on higher mileage for their 3-season tire lines.
https://www.tirerack.com/tires/tiret...jsp?techid=125
Winter / Snow Tire Tech: What is the Three-Peak Mountain Snowflake Symbol?
A three-peak mountain snowflake (3PMSF) symbol branded on a tire's sidewall indicates the tire meets required performance criteria in snow testing to be considered severe snow service-rated. Originally used as a designation for winter tires, the 3PMSF symbol is now featured on some all-season and all-terrain tires with snow performance that meets the testing criteria.
Testing measures a tire's acceleration traction on medium-packed snow only. Braking and turning on snow, along with ice traction are not components of the test.
Tires branded with the 3PMSF symbol are expected to provide improved snow traction beyond a standard M+S branded all-season tire.
Note: 3PMSF-branded all-season and all-terrain tires cannot match the traction of dedicated winter / snow tires in all winter weather conditions and should not be considered a replacement for where and when a dedicated winter tire is needed.
In 1999, The U.S. Tire Manufacturers Association (USTMA) and the Rubber Association of Canada (RAC) agreed on a performance based standard to identify passenger and light truck tires that attain a traction index equal to, or greater than 110 (compared to a reference tire which is rated 100) during the specified American Society for Testing and Materials traction tests on packed snow. The standard helps ensure drivers can easily identify tires that provide a higher level of snow traction, and tires meeting that standard are branded with the three-peak mountain snowflake (3PMSF) symbol.