Archive for March, 2009

So Eric’s belt-drive commuter is done (still waiting on the drivetrain, watch this space!) and it’s a knockout:

  

   

   

And here are some closeups of the detachable seat stay:

  

And now it’s time for another ANATOMY OF A PAINT JOB! Are you excited?
It all started with this mockup that Eric sent me. We later decided to do the writing in white, and I adjusted the size of the seat tube panel to reflect his frame dimensions:

So the first thing you need to know about all our paint jobs is, it’s all paint. We have decals for our logos, and we cut a ton of vinyl, but it’s only as a stencil – we don’t use any vinyl on the finished bike. When you see plaids or lace or any other graphics, it’s all paint. So a checker pattern? That means designing the band in illustrator and sizing it precisely so it will wrap all the way around. The frame has been primed (using white primer which will help the yellow pop) and I’ve sprayed white generally where the bands will be:

   

You can see I’m using a piece of tape as a guide to lay the checks down. Next I spray yellow on any areas that will be yellow, and then I apply Spray Mask around the lugs and dropouts. That dries overnight and then I use an x-acto to cut a nice line and mask off everything that’s going to stay yellow:

   

And then I shoot black:

 

Now comes the “fun” part, fun in the sense of terrifying and painstaking – pulling off the bandages! I’m using a wood paint stirrer that I filed into a ramp to get all the checks off, and of course they get everywhere. But when I’m done, it’s ready for decals and clearcoat!

  

Then I polish up the head badge and dropout faces, apply Frame Saver, and it’s ready for components!

Next: finishing AJ’s tourer, more Geekhouse, and hopefully, belt drive in action!

For our friend Eric we’re building the first belt-drive Circle A. When we get all the components sorted out, I’ll be talking about how (& how well) it works, but first there are some oddities that we have to address when building the frame.

The first is that, because unlike a chain you can’t add or remove links and thus easily change the length of the belt, you have to determine a precise length for the chainstays that takes into account cog size, “chain” ring size, and belt length. Eric wants a single speed, so we had to be sure that the he was going to be happy with the gear ratio – there are some other combinations that will work (we used dropouts with extra-long slots), but it’s much more limited than with chain drives. Fortunately Gates, who makes the drive system, provides a spreadsheet that helps you determine the chainstay length.

But the real challenge, and related to the above issue, is that because the belt doesn’t come apart, the frame has to. WHAT?! I know. It looks a little something like this:

Now you can get around this issue with an elevated chainstay, like on all those old Haro and Nishiki mountain bikes from the early 90’s. But Eric wanted a classic looking lugged frame, so I wanted to make the disconnection as svelte as possible. Using our own dropouts, laser cut next door in Pawtucket, I modified an old seat stay end to become a detachable dropout/stay interface:

  

Eric and I are working out the Yellow Cab themed paint; I’ll post pictures of that and the components as they arrive.

Speaking of Nishikis, I repainted one for Miguel in Austin. We saved the chrome on the dropouts and painted it a deep pearl blue:

   

   

And finally I just started a touring bike for my friend AJ, I’ll start brazing next week. He’s using Richard Sachs lugs and all True Temper tubing. Note the dimpled chainstays to give him some more tire clearance:

  

Next: more belt drive action!