Strong. Light. Disk brake compatible. Spirit disk cranks result from a sophisticated effort to develop the highest possible strength to weight ratio and pedalling performance in a unicycle crank.
Spirit disk cranks allow installation of a standard disk brake rotor (not included) to the right hand crank. This enables the rider to install a disk brake (see compatibility requirements below) and maintain an efficient pedalling stance, minimal weight, and the strongest possible wheel geometry. The rotor attachment is hardly noticeable for riders choosing not to use disk brakes. All cranks have double pedal holes for versatility.
Features:7050 Aluminum (similar yield strength but tougher than 7075 Al)
Compatibility Requirements: (Per Kris Holm.com)
Important Warning for Use of Spirit Cranks with KH/Schlumpf Geared Hub
KH/Schlumpf geared hubs contain a knurled (rough) bearing on one side. This knurled bearing surface acts as a brace against the tightened bearing housing when you are in high gear mode. Because crank-mount disk brakes apply braking force through the crank, braking in second gear may apply additional force to the knurled braking surface beyond that experienced during normal pedalling.
This additional force may increase the risk of slippage of the knurled surface. Slippage problems were not identified during testing. However, given the newness of this braking technology and wide range of users, we cannot guarantee that slippage of the knurled bearing will not occur for all users under all conditions. Slippage of the knurled bearing in the frame while riding in second gear will most likely lead to falls and could lead to possible injury.
Riders using Spirit Disk Cranks with KH/Schlumpf Hubs do so at their own risk. Check the tightness of bearing housings on a regular basis. If you experience slippage, do not use disk brakes with the KH/Schlumpf hub.