I had 4.5" wide fat tires on a rad rover electric bike. They were to wide for dirt trail's. Knobs on them kept trying to pull the bike up the shoulders of the trail. resulting in a zig-zag pattern that was impossible to stop...So I got a set of the Beach Bum smooth tread tires and a pair of tuffy tire liners. Problem solved. Just a little bit of a wobble in gravel but on deep trails and pavement they work great...save the knobbies for winter snow and cross country rides in the eastern washington desert country where I live. Any tube type tire with a tuffy tire liner I have used has NEVER had a flat. Its a bullet proof combination. Keep them aired up and they will go forever, cactus spines and puncture vine (goat heads) will not puncture them.