In 2022 i had the oportunity to spend two weeks with Koichi Yamaguchi hand-building my own bike frame, fork, and stem. Since then I have not had the chance to build anything else, but I have recently been inspired to try it again.

At the Yamaguchi Framebuilding school, Koichi teaches brazing with oxy-acetlytne, mixing silver-braised lugged and bronze fillet brazed components, and all tubes are cut and miteded by hand with files.

For my build, I plan to utilize the tools available at Denhac, a makerspace in Denver, which includes a metal shop, woodworking, laser cutters, and 3D printing facilities among others.

The Bike

I’m no longer interested in racing, and aggresive road bikes, and care more about just having fun on a bike getting around town. Because of that, I wanted to build a single speed mountain bike / clunker / big-BMX bike of sorts.

Looking around for existing examples, I found the Surly Low-Side, which Surly describes as the bike that gets you across town for a quick rip on singletrack, then over to the bar for a night out, which sounds perfect.

I’ve decided to use this frame geometry as a starting point, and modify it instead of starting new.

Coming up

This is the first of a series. Things I want to cover as the build goes:

  • Learning to TIG weld I learned brazing at Yamaguchi, but I want to build this one with TIG, which means learning it first. I have had some practice, but plan to start with a lot of practice before moving onto any frame fabrication.
  • Geometry, Parts & Tubing Starting from the Lowside numbers and modifying them to suit me, then picking tubing and components around that.
  • Building the jig I need a fixture to hold all the tubes square while I tack and weld, so that gets built before any real tubing gets cut. There are multiple directions I could take here, including making a non-adjustable jig setup only for this frame, or creating something which could be used for future builds.

Surly Lowside *Surly Lowside: The bike that gets you across town for a quick rip on singletrack, then over to the bar for a night out. *