SHIFT™ (Spoke Hole Impact Forming Technology)
One benefit of American manufacturing and materials is the exposure we have to aerospace and defense critical technologies available nowhere else in the world. The SHIFT technology seen in our hubs is a perfect example of this. Many manufacturers use 6061, a very inexpensive alloy, but these designs require more aluminum mass in the part (more weight) and can be less efficient to produce on modern equipment due to its soft nature. The upside of 6061 is that is very tough, or resistant to cracking, so it will make hub flanges that can deform easily but generally will not crack. Through intense development with Alcoa Zipp has moved to a proprietary alloy called Z310.9 which is nearly twice the strength of 6061 while being slightly more crack resistant, and further increased the performance through a radical manufacturing process called SHIFT: Spoke Hole Impact Forming Technology.
But here comes the high technology part of the exercise. The Zipp team developed an impact forming process to essentially forge each individual spoke hole to eliminate stress risers, develop favorable localized grain structure, and increase localized hardness all at the same time, and Z310.9 became the perfect alloy for the job.
The other beauty of the SHIFT process is that instead of removing material from the flange as in traditional processes, all the original material remains, and is simply forged into the surrounding flange geometry.
The only downside of this shift technology is that the tooling is specific to each spoke count, and is very expensive. Currently 16, 18, and 24 hole front hubs are made, and 20, 24 hole rear hubs are made, which seems to fill most any need. The overall flange performance is so dramatically improved that radial lacing will not void the hub warranty, and is even acceptable in cyclocross wheelsets.