O'Curren builds a coaster brake racer

[Ratpick]

I haven't been on here in a while, but since I just finished up a bike I thought it'd be nice to share. Some creativity, and just a little bit of skill and knowledge can go a long way. I made a bike, and it rides great.

This was a build, mainly, for the Coaster Brake Challenge that goes on out here in the 818 of LA. But also since I mostly went mountain biking on my other coaster brake racer I knew I'd be riding this thing a lot anyway, so I wanted to make a real mountain bike out of it.

I started by with a lowly 1995 Schwinn Frontier

 

[Ratpick]

Then, cut out the part of frame I want to use

 

[Ratpick]

Next was to set up my jig (which I just got, and it's awesome) with a starting point for my geometry.

(That's not a frame I built, but I made it mine and quit advertising for whatever company it was)

Then started to set up for this build. The front end geometry was changed slightly

 

[Ratpick]

This next part of the build was actually done in just a day. Making tubes, fitting and splattering together. Making some sexy curvy tubes? Well that takes a high end tubing bender

Then a few fit in place

and a couple super-seatstays make it a frame

I did plan for the asymmetrical design, but actually wanted a little more spread. It's not that easy to place the tubing just like you want when it's actually happening, and I was sort of rushing myself a bit. If you notice on the floor behind was the first attempt at the down tube that didn't fit right. I decided not to redo and just slap these on. Along with a really rad gusset.

Another shot to show that amazing weld quality. It did stick, ok!

Also, please note the other horribleness that I don't recommend mimicking though it will work- friction cutting everything. That's a regular wood-type chop saw in the background with a friction metal blade. That grinder you see is what mitered and fit the ends of all the tubes. It sucks. Heat. Sparks. Dust. Slow. But it worked and it got there. Don't leave the idea un-built because you didn't buy all the fancy tools.

 

[Ratpick]

Then it got painted and assembled and became a bike.

Note the crafty brakearm stay and the extra file work I did on the gusset-opener section.

 

[Ratpick]

Then to top things off I was able to make another idea come to fruition. I have a good homie that started working in an excellent space-age fab shop. He machined me a wonderful little heat sink.

 

[Ratpick]

That's all for now, though I should add some fresh pics since it got some slight cosmetic upgrades. Also the rear wheel for this bike isn't built yet so maybe I'll show that soon as well.

 

[pebblewurm]

I like the heat sink! Is it an off the shelf part for another application?

 

[deven_science]

Strange idea for an asymmetrical design. Gives me some cool ideas, though I would have made the difference more pronounced, just to make it clear that it was intentional. Not bashing, I salute anyone who's willing to take a crack at fabbing their own frame.

 

[DJ Bill]

That jig is just great! Where'd ya get it? Or didja make it?

 

[Ratpick]

The heat sink started as an inget of aluminum, then a few hours on lathe and mill made it happen. I have tentative plans of casting copies so it can be an on-shelf item

You're right on wanting to pronounce the asymmetrical design more- that was original plan but this build was sort of just practice/ test run.

The jig is from a company called ChopSource. It's intended for motorcycle but, as you can see a bicycle is easy breezy. They sell just the laser-cut plate pieces and cones then you get some square tubing and put it together. I think a crazy-stretched chopper bike is coming up soon.

 

[ryan.branson.96]

nice build,I have a friend that used to work for British aerospace and can do awesome work with aluminium,downside is it costs a lot here in NZ


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[Ratpick]

Hey Thanks!
Here it is with a new seat and less decals