Boundary cranks are the latest offering from Kris Holm to enable the highest possible strength to weight ratio and pedal performance in a unicycle hub.
The Boundary hub uses the Q-Axle micro spline, which has a larger (24mm) diameter compared to the ISIS-type 22mm, enabling high strength at 33% lower weight than the KH Moment and Spirit hub.
Cranks are fixed by tightening two bolts on the crank, which makes them easy to install and remove without wear-and-tear on the splines.
The 42 mm bearing and 100-mm bearing-bearing spacing is compatible with all ISIS-ready frames.
Flange spoke hole size are optimized for 14g spokes (2.5 mm, 0.5 mm bevel)
Sealed, 42 mm bearings with standard 100 mm spacing
Flange width Center flange to center flange mm, Flange diameter mm
Bearings: 42 x 24 x 12
Please see our spoke calculator for this information
Note: This hub utilizes 42mm bearings, and is compatible with 42mm frame/bearing housings only.
Bearing Size: 42x24x12mm
Brand - Other: Boundary
Number of Spokes: 36 Hole
Type - Bearings: 42mm