You may have noticed that flange angles are something rarely mentioned in a discussion about hub quality or design. The reason for this is most hub manufacturers don’t put much effort into proper flange alignment. At Project321 we think it’s one of the most important aspects of a hub shell design and results in stiffer and longer lasting wheel builds.
Take a look at your current hubs. It’s almost assured that the outside spokes exit the hub, head toward the nipple and make heavy contact with the hub flange. The initial result is a stress riser in the spoke and flange. But the bigger problem is the lateral load on the flange. The more directly the flange is pointed in the direction is being pulled, the stronger and stiffer it will be.
We also believe a properly angled flange leads to longer hub life which in turn allows us to offer our industry leading 10 year hub shell warranty.
So the question becomes, what is the correct flange angle? Well, we have run a lot of numbers and averaged a lot of ERDs and bracing angles to set what we think is the most appropriate flange angle for the wide range of rims on the market today. Every hub we produce has a different flange angle based on the flange spacing and diameter. In the end, we have more flange angle than any other hub manufacturer and less lateral flange loads. Take a look at the following diagrams.
Good flange angle closely aligns with the bracing angle and eliminates contact with the flange. (Note the spoke angle at this point does not match the bracing angle because it’s headed over to cross the inside spoke.)