Clutches for land vehicles and structural parts therefore and clutch release systems for land vehicles comprising release bearings, release levers, release hydraulic units and release tools sold as a complete unit; dampers in the drive train of land vehicles; clutch repsets for land vehicles comprising clutches, discs, release bearings, pilot bearing bushing; flywheels for land vehicles; dual mass flywheels for land vehicles; clutch release cables for land vehicles; clutches for agricultural land vehicles and repsets comprising clutches, discs, release bearings, pilot bearing bushing