The emergence of 32-inch wheels in mountain biking has prompted a reevaluation of axle standards, with the Super Boost 157mm rear hub gaining prominence. This development addresses the increased lateral flex associated with larger wheels, enhancing overall bike performance.
The Return of Super Boost
Newmen Components, a German wheel manufacturer, has highlighted the significance of the Super Boost standard for 32-inch wheels. They assert that the increased wheel size leads to greater sideloading on the hub, necessitating a wider rear axle to maintain stiffness and strength. This insight is detailed in their recent white paper. (bikeradar.com)
Understanding Super Boost
Super Boost is a 157mm-wide rear hub standard that originated in the early 2000s, primarily for downhill bikes. As wheel sizes increase, the leverage on the axle also rises, leading to more flex. Newmen’s research indicates that a 32-inch wheel flexes 31% more than a 29-inch wheel under the same lateral load. To counteract this, widening the rear hub spacing is essential for maintaining wheel stiffness. (pinkbike.com)
The 32-Inch Wheel Revolution
Larger wheels offer advantages such as better obstacle clearance and increased traction due to a larger contact patch. However, they also introduce challenges like added weight and potential flex. Manufacturers adopting 32-inch wheels aim to enhance wheel and bike stiffness without significantly increasing weight. A wider hub, like Super Boost, provides increased stiffness with minimal weight gain, making it a practical solution for 32-inch wheelsets. (mtb-mag.com)
Industry Adoption
The adoption of Super Boost is gaining traction among manufacturers. Zinn Cycles, for instance, utilizes the wider Super Boost rear end in their 32-inch bikes, moving away from the more common 148mm-wide Boost size. (bikeradar.com) Similarly, DirtySixer employs the 197mm fat bike rear-hub width standard for their 32-inch bikes, aiming for even stiffer wheels. (bikeradar.com)
Conclusion
The shift towards 32-inch wheels in mountain biking underscores the need for axle standards that accommodate the structural demands of larger wheels. The Super Boost 157mm rear hub standard addresses these challenges, offering a solution that enhances wheel stiffness and overall bike performance. As the industry continues to evolve, the adoption of such standards will be crucial in optimizing the benefits of larger wheel sizes.