Free hub ratchet design
We are using a totally new design for the Hi-Per hub when compared to our JB03 hub. The Hi-per uses 6 pawls with leaf springs and an alternating engagement pattern to double the engagement of the 72T ratchet ring. This results in 144 points of engagement which is lightening fast whilst also making all the right zinging noises when freewheeling. This system is more robust and can better withstand contamination due to the course nature of the ratchet ring and the one piece free hub body.
Bearing size and position
We paid special attention to the bearings for this hub design. Considering the bearing position, size and availability. The rear hub runs on 6902 bearings in the shell and free hub body. The free hub body’s inboard bearing is positioned directly in line with the ratchet ring which reduces leverage on the bearing and increases durability. In the front hub we have used 6903 bearings with an axle and fixed end caps, which does away with the floating style end caps of our other hubs. These bearing sizes are commonly available and are easily replaced once worn out.
The tapered hub shell design ensures a direct path from critical components like the drive ring and brake tabs, resulting in a lightweight rigid structure. The hub flanges are slightly tapered and are designed around 27.5 and 29” rim ERD dimensions which reduces spoke fatigue.
HOW WE DESIGNED THEM
We spent over a year designing and developing these hubs. The first step was to 3D model the concept in CAD. We used 3D printed prototypes to fine tune the 3D model.
The next step was to ride test aluminium prototypes. We used E-bikes to do ride test the hubs in order to accelerate testing. After a few small design tweaks to the free hub, we sent off the final design to Tawian for mass production.