Sometimes doing a project because it’s fun is more important than doing it to actually save a buck or whatever other excuse people often give
This project started because I was curious how the inside of this hub worked. While disassembling (without even looking at an assembly diagram beforehand, idiot me) I managed to mangle the axle. A quick google search revealed my expensive, and fatal, mistake. No replacement parts, so the disc is toast. Luckily, I got it on craigslist for only $200 so I wasn’t out a tremendous amount. However, I wasn’t about to throw away a perfectly good wheel over something like this, and I needed another rear wheel for my track bike anyways.
I’d heard of freehub to fixed gear conversions before- typically on Shimano hubs, which this fortunately is. The idea is you replace a splined and replaceable freehub with an aluminum monolithic assembly with track threading. Since you also no longer have the bearing integrated into the freehub, you have to install a cartridge bearing into this monolithic aluminum design and have the appropriate nut to support the inner diameter of the bearing against the axle (it cannot ride on a threaded axle, your hub would disintegrate no matter how much preload you put on it.)
The first version of this design I was aware of was the Surly FIXXER which was supposed to convert most shimano wheels to fixed gear. Unfortunately, it hasn’t been in production in over 10 years. Walker brothers wheels also makes a version, so I bought theirs to see if it would work for me.
Unfortunately, it did not work. The splines were the wrong pattern and not large enough. Additionally, that product works with 10s wheels, whereas the longer 11s freehub would have meant a too-inboard chainline.
After a bit of measurement, I was able to CAD up a design I thought would work, and sent it to my trusty go-to machine shop: Rapid Direct. I had the part machined and in my hands in under a week. The internet is beautiful!!
Anyways, the disc works like a charm. Pretty pleased with it, and looking forward to racing it on the track for years to come.
If any of you have a similar desire, I discovered that pretty much any rim brake dura ace hub has the same freehub PN- so if you want to do the same, send me a message or comment below and I will shoot you the CAD file and instructions on how to get it built.
OTB Engineering 