Seattle’s rainy fall started today, which can only mean one thing: time for me to build a bike. In the last year I’ve ridden all but about 200 miles on my new bike Gifford. I like having a slim stable, but I also kind of miss having a second bike.
A few months ago I posted about getting this frame from Brandon Ives of IvyCycles. The frame came to me with most of the hard work done (the front and rear triangles were done) and ready for all of the detail work. I love the detail work, so this is a great partnership. The brazing that he did looks great, hopefully I can keep a high standard on my part of the bike.
I call this bike the Ivy-T because it is heavily inspired by one of my favorite mass produced bikes, the Bridgestone RB-T, but built by IvyCycles. The frame geometry is more or less a copy, just resized slightly to fit me better. We used lighter tubing and better lugs that the original, but it is still Ishiwata tubing (this bike has 019 (8/5/8), the original used 022 (9/6/9)). I still need to build the fork, but the bike will get a low trail fork that looks similar to the ones on my other bikes. I’m going to use this fork crown:
Mitsugi Crown from Kirk Pacenti (bikelugs.com). The link takes you to the stainless version, but I'm using the normal steel one.
In the spring I was lucky enough to find a set of Dia Compe Grand Compe 450 centerpull brakes. They came complete with braze-on studs, and had never been installed! I’d been wanting a set of these brakes since first seeing them on a bike that Mitch Pryor (MAP Bicycles) brought to the 2009 Oregon Handmade Bicycle Show. Centerpulls never really got my attention before, but I love the way these look. They are a nice mix of refined and mechanical at the same time. I watched eBay for a while and never saw any go by, but then these ones showed up on the BOB list. I jumped on them. Mitch was very helpful and emailed me original documentation for these which showed where the studs should be installed (the critical dimension is 62mm between the studs, although anything between 62mm and 65mm looks good to me).
Over the last week I made some curved bridges for the frame and brazed on the studs for the rear brake. Here is are the photos from that process.
I made this 3" radius bender using a circle cutting jig for the router and some scrap plywood. It was made in two halves with a chamfering bit.
This is what the bender looks like when assembled. To use it I just clamped it into my vise, trapping the end of my 3/8" tubing underneath. I pulled the other part around by hand.
I made this simple jig for holding the studs in place. I took this photo after tacking the studs, I wanted to check alignment before finishing the brazing.
I took this photo just after putting the torch down, but before removing the flux.
The flux has been soaked off. I'm pretty happy with how this brazing looks, I'm really out of practice. You can also see the curved bridge here.
Tons of clearance under these very pretty brakes. They are listed as 55mm reach, but I've never seen a 57mm reach dual pivot with this kind of clearance. The curved bridge hides nicely behind the brake arches.
I was really worried about having the gap between the brake arms be consistent and small. A little misalignment of the studs is barely noticable with cantilevers, but could cause big problems or look terrible with a centerpull.
One final shot of the installation, where you can see how the springs work.
Before installing the bridges I indented the chainstays slightly for increased tire clearance. I hadn’t planned on doing this originally, but the brakes fit larger tires than I expected (my 38mm wide studded tires fit), and the chainstays were the limiting factor on tire clearance. These photos are for JimG, who has asked me in the past for photos of my chainstay indenter.
I intend the chainstays on my 3" vise. Sometimes a skinny vise is useful!
Post indention, before bridge installation.
This is what the indenting form looks like. I made it from 5/8" rod, filled down to a reasonably nice shape, and brazed to a small piece of angle iron.