High quality butyl tube ideally suited for confident and reliable use on 27er MTBs. The new ContiTube bicycle tube program makes it easier for you to find the ideal tube for your cycling demands. The user-friendly tube system is suitable for any size, length, design, type of valve and is perfect for any tire dimension and riding occasion. Varying tube types can affect your tires handling characteristics: the Standard tube, available in all dimensions is the best choice for everyday cycling whilst Light & Supersonic varieties give racers the option of lower rotating weight, therefore increasing speed. The lightweight tubes have a lower thickness and so it is imperative that inflation pressures are maintained to prevent the risk of pinch flats. Shorter valve inner tubes are ideal for wheels with rim depths of 24mm or 30mm but are not ideal for wheels with rim depths of 40mm or above (as the shorter valve would not extend out of the rim valve hole). Presta valve tubes are most commonly used for road wheels (700c) and on a few MTB wheels as the valves are thin, whereas Schrader valves are more commonly found on MTB wheels as the valve is larger and won’t fit through 700c rim valve holes.