MS3 - Soft / Intermediate Terrain. MH3 - Intermediate / Hard Terrain. For the M12 and S12 tires, the sizes are as follows: 100/100-18 = Michelin size of 120/90/18. 100/90-19 = Michelin size of 120/80-19. 80/100-21 = Michelin size of 90/90-21. Note: Please check your current tire size to ensure you are ordering the correct replacement size.
"I ride in all differant terrain and this tires shreades it all from rock to mud, mountain trails and sand it is a very durable long lasting tire that hooks up awsome the best thing is when your done riding half your tires not gone"