Background

The shift in the last decade toward big drops and aggressive riding has drastically increased the loads a bicycle experiences. Component design has evolved to effectively handle these high forces. The spline bottom bracket/crankset interface is one example of this evolution in components. A larger diameter spindle combined with an efficient spline crankarm connection has become necessary for these components to keep up with current riding. Unfortunately, the existing size constraints of the BSA bottom bracket shell severely limit the load capability and life of bottom brackets. 

If the bicycle industry wants bottom brackets that last longer, are more durable, and can handle the continued growth of “extreme” riding it is necessary for the bicycle frame itself to change. This change offers obvious advantages for Free-Ride, Dirt Jump, Urban, BMX, and Downhill riders but also offers huge advantages to cross-country and road riders in the form of bottom bracket longevity.