Thursday, March 29, 2012

Braaap! Braaap!

Well, I guess I've been working on this post for about 6 months now... it's been a busy time to say the least, but at least I finally got some pictures uploaded! Back at the tail of last summer, my good friend JP over at JamesFrames was finally able to finish up a frame that I had asked him to build for me. I wanted a new single speed frame, but wanted "real" 26" wheels, and most importantly for it to be compatible with the Gates Carbon Drive system!
The real struggle I had, was sourcing a set of dropouts that I liked (from a technical standpoint), that weren't ridiculously over-priced, and that could work with the necessity to have a break in the frame in order to install the Gates belt. My search led me to Black Cat Bicycles who not only make some absolutely stunning bikes, but also create some of their own frame components like dropouts. And I saw that they had modified a set or two of their dropouts to run with the belt system, and that I might be able to do the same. The swinger-style dropouts they have were very similar to my ideal setup as well, as they have a couple features that make them particularly well-suited to the demands of running a belt... pay me and I'll explain those secrets to you :)
I also really wanted a super-clean design, that didn't make it obvious that the frame had a "break" in it for the belt. I'm quite happy with the solution and how things came out. I think it could be refined a bit if we did it again (and spent a little more money on machining), but unless you look for it, the difference between the two dropouts is nearly unnoticeable.
I was a bit limited in what chainring/cog combinations I could run (though the gearing choices were fine), due mostly to availability, since a lot of the belt stuff has been centered around the demand for 700c mountain bikes. We needed a bit more clearance in the frame, so JP made a nice little "notch" in the chainstay for me, and we actually ended up with more room than we needed. Plus, I have a new Gates CenterTrack drivetrain coming now, and that will make this notch nearly unnecessary.
My first choice for the frame actually would have been aluminum, but it's basically impossible to source aluminum dropouts with a break in them. So steel was the way to go. It's also important to have a nice stiff frame, so that the belt tracks well and doesn't cause any alignment issues (though the CenterTrack system is MUCH more tolerant to any alignment issues). But a stiffer frame is generally heavier... and in keeping with the idea of trying some new stuff on this frame, JP and I came to the idea of using an integrated, carbon fiber seat tube from Enve. We figured this would shave some weight as well as add some uniqueness to the bike, and perhaps even a little bit of vertical compliance.
I think it came out great! The tube is bonded at both the seatstay/toptube juncture and at the portion of seattube extending from the bottom bracket.
Overall, I was very pleased with the way the bike came out! And riding it is a dream! It's built with fast race-geometry, is pretty light for a steel bike, and just rides like an absolute dream! The bike is completely silent with the belt drive setup, and it requires basically zero drivetrain maintenance.