20 inch unicycles, just like the smaller unicycles are good for learning and having fun. The larger running wheels from 24-29 inches are suited for athletic cycling. Today the unicycle can be applied in a variety of ways. There are, for example, cyclists who use their unicycles on off-road terrain where they ride trails and do jumps. Or on the other hand there are bikers, who use their really big unicycles for road races. Depending on terrain these bikes are equipped with rough profile or road worthy tyres.