M12XC = Intermediate Terrain. S12XC = Soft Terrain. 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.
"Found new tires for the CR250 and the Michelin prices were the best anywhere. Only issue was they number them differently than other brands so was a little confused when I got them Called and they straightened me out :-) Arrived super quick and with free shipping. Doesn't get much better...."