How did the current lineup of Zipp wheels (tubeless with hookless rim-tire interface) achieve significant weight reductions from previous models?
Going back over five years, we started with a “clean sheet” project—a clean sheet of how to make our rims. With rim-brake wheels, we tried to lead the way to be the first to have a carbon clincher that could withstand the temperatures from braking on the carbon braking surface. That was a massive project. But the requirements changed when we went to disc-brake road bikes. We no longer had to dissipate heat on the carbon braking surface. There were grumblings in the cycling industry that hookless might be a path forward. Just a few years ago, hookless and tubeless were rare things for road bikes. So, we started this clean sheet project; we could make a different rim. The advantages of going to a hookless design allowed us to design the wheels to be lightweight.
Zipp wheels are now hundreds of grams lighter than before. How does this change how riders evaluate the wheel model and rim depth best for them?
It changed from correlating mainly the rim depth with the type of riding (such as 404 for road racing, 303 for hills or gravel) to looking at other rim specifications. The internal width is one super-important part of the rim. Our 303 Firecrest and 353 NSW are 25mm internal width. That allows you to ride 30, 32, and 34mm wide tires. You move up the rim dept to 404s, 454s, 808s, and 858s; those are 23mm internal. A 28mm tire is going to fit nicely. But you also still want to think about weight. With the weight drop, you don’t have to think, “I can’t put a set of 858s on for a crit because they’re heavy.’ Now they’re about the weight of what a 404 used to be.