Lets hear your input regarding this issue. I have tried the Pirelli MT21 and I am not overly impressed as some of the reviewers in the mags. I have my first Kenda TrackmasterII on right now and have noticed that it seems susceptable to chunking. I run on pavement 30% only to get to certain trails if I don't feel like hauling or to go gas up. Would like to know if any others are worth trying? Forgot to add - mostly soft and sandy conditions in my local riding area. Thanks to all that reply.