Michelin Bib Mousse, foam core insert that replaces rubber tubes in off road motorcycle tires. Sponge-like circle of Butyl honeycomb foam whose tiny cells are charged with nitrogen. Smooth molded outer skin is designed to slip into specific size off-road motorcycle tires. Developed by Michelin for expert racers who MUST FINISH EACH RACE. When you cannot tolerate DNF, get Bib Mousse.