Michelin Bib Mousse (120/100-18 or 140/80-18) Invented by Michelin&#174;, Michelin Bib-Mousse&#174; has an unparalleled number of victories and championships: 26 victories in the Dakar Rally-Raid since 1983, 22 Enduro World Championship and 7 Motocross World Championships! Michelin's Bib-Mousse&#174; It is a sponge-like circle of butyl honeycomb foam whose tiny cells are charged with nitrogen. Lighter than a heavy duty tube, Michelin Bib-Mousse&#174; offers an equivalent pressure of 13 PSI (0.9 bar) and removes the inconvenience from a puncture. The smooth molded outer skin is designed to help it slip into its specified size of off-road motorcycle tire (Michelin tires ONLY). Developed by Michelin for expert racers who must finish each and every race.