As downhill courses get gnarlier our products evolve with the topography maxxis downhill tubes are 15mm thick to eliminate pinch flats add stability and allow the use of low air pressure the large 26x2527 size fits our entire range of downhill tyres maxxis downhill presta 26in inner tube 15mm thick walls downhill specific presta amp schrader valves presta valve with rvc is removable valve core