I ride muddy trails and I run 20" Fast Trekkers I don't hardly have any problems. If you ride in alot of mud get yourself some GBC Paddlemasters they are paddles for mud and snow, you will be able to go through just about anything. The paddlemasters are great when a 4x4 gives you crap about a two wheel drive, 400 lbs plus rider Banshee with the fastest spinning paddles on will beat a 700lb plus rider 4x4 through the mud anyday.