A square profile provides a solid, consistent feel across the knobs. Modified knobs on the shoulder and centre improve braking performance and traction on hard surfaces. When gravity pulls you downhill, rely on the High Roller II to keep you upright. Downhill (dh) casing: two layers of casing material are used from bead to bead, providing additional protection and sidewall stiffness for downhill applications. open tread design improved braking and traction 3c maxx grip dual-ply casing with butyl insert Butyl insert an extra piece of butyl rubber that extends from the bead of a downhill tire up into the sidewall. The butyl insert helps prevent pinch flats, protects the rim from hard hits and adds sidewall stability Rubber compounds The most important part of a tire is arguably the rubber compound within the tread. By changing the amounts of various components of the rubber formula, engineers can make two identical looking tires perform completely differently