Exactly, and how would they get an all season rating?
Here's the definition of "All Season".
https://www.ustires.org/system/files/files/2024-10/TISB_10 no8 September 2024_0.pdf
And here's the history behind that definition (lifted from my webpage
Barry's Tire Tech: Winter and All Weather Tires):
When radial tires were introduced in the 1960’s, it became apparent that they had better wear characteristics than regular bias tires. That meant that tire designers could use more aggressive tread patterns and not suffer wear issues. Eventually, SOME radial STREET tires had very nearly the snow traction of the commonly used “Snow Tires”.
Many tire manufacturers started producing such tires under the “All Season” umbrella.
This created a problem in California where the California Highway Patrol required “Snow Tires” or chains on certain highways during certain inclement weather. CHP requested a way to tell what was and what was not an All Season tire.
At the time, snow traction testing was in its infancy – not reliable and not repeatable.
So the RMA (Now the US Tire Manufacturers Association) created a verbal description of what an All Season tire was and allowed tire manufacturers to use the letters “M” and “S” with some sort of divider between those letters, such as “-” , “/”, “+”, etc. You can see that today on all All Season tires.
Here’s a link to the verbal description of what is required to get the “MS” symbol:
USTMA Snow Tire Definition for Passenger and Light Truck Tires – 2024 version
What I find interesting is that in spite of the shortcomings of the “MS” symbol, snow tires basically disappeared from the US market for about 20 years (except for a few locales).
Over the years, consumer’s expectations for snow traction has grown – as well as the tire manufacturer’s ability to deliver better snow traction. Needless to say, the “MS” designation just doesn’t work anymore.
