26''s GNCC type stuff. Mud, dirt, sand, water. lol Mainly stuff that sport quads race through in woods. Some races get pretty nasy tho. I am a track sweeper for 3 local cross country racing series in Indiana. When the racers break down in the woods I pull them out and back to there pits. My Mudlites have worked great for it for the last 2 years. 1 of the back tires have a sidewall hole with 3 plugs in it and tread is starting to wear down. Front tires still look good for being almost 6 years old, the back are getting a little rough.