I have only raced on prepared surfaces. The only tracks that my MTX4 have been on so far are the Silver Bowl Raceway (las vegas), Revelation Raceway and Crystal Park Raceway (both in southern california). As I said, they are all clean and prepared dedicated raceways. Perhaps a dirtier track is causing your belt cracking? It doesn't sound like you are having any major issues, as belts do wear out no matter what you do.