GM Service Manual Online
For 1990-2009 cars only

Most vehicles are now equipped with steel-belted all season radial tires as standard equipment. These tires qualify as snow tires, with a 37 percent higher average rating for snow traction than the non-all season radial tires previously used. Other performance areas, such as wet traction, rolling resistance, tread life, and air retention have also been improved. This was done by improvements in both tread design and tread compounds. These tires are identified by an M + S molded in the tire sidewall following the size number. The suffix MS is also molded in the sidewall after the TPC specification number.

The optional handling tires used on some vehicles are not all season tires. These will not have the "MS" marking after the tire size or the TPC specification number.