Design Philosophy

Rim Design 

 

 

There has been a sizable change in carbon rim manufacturing lately, creating "hookless" interfaces to tires. We don't use this design at Kappius. And here's why.

For the record, we've never had a single Kappius rim fail at the bead.

Actually these are excepts answering inquiries from customers by me, Russell Kappius.

From an engineering perspective I pose this question: "Yes, you can do it, but why would you?" The only logical argument that I can agree with is that it's easier to make. Any argument saying it's better fails on me. The only argument I'll give a bit on is strength. The strength of hookless rim may be higher because of some fundamentals, but it's counteracted by requiring a taller sidewall. Taller sidewalls are more likely to encounter a rock strike when compared to a shorter sidewall like ours.

The other strength argument I've heard is that hooked beads on carbon rims require "soft" molds. These soft molds do not compress the carbon as much, leaving it a lower modulus. This is NOT true with Kappius molds. While it might be a bit harder to envision initially, our molds are made in a way that do not require soft parts, and the carbon on the hook is just as good as the carbon elsewhere.

To me, the performance of a hookless design can only be inferior to a hooked bead. This is due to the shape of the tire bead and how it interfaces to the rim. Hookless interface very poorly, resulting in unnatural bending of the tire casing.

Lastly, if hookless were better, why aren't aluminum rim manufactures doing it? I'll tell you why: Because it's just as easy for them to make a hook as not, and they know hooks work better!