This Space for Rent

Convincing me to take up framebuilding, one crash at a time

This afternoon, while on the way to the store, the front wheel of the trek wobbled sideways just as I started to accelerate away from a stop, which trapped my foot on the wrong side of the wheel and resulted in a slow stately starboard capsize.

Which, thanks to not being able to get my foot untangled from the wheel and my pedal in time, ended up crunching my right side into the street and leaving me with an impressive bit of road rash on my right elbow and a bruise or torn muscle in my ribcage.

Add to this the problems I have squeezing fenders under the fork (when I’ve got 28mm tires on the bicycle, I can’t get a fender to thread between the brake and the tire. I’ve tried cutting holes into fenders to make them clear the brakes, but what ends up happening is that they vibrate to destruction much faster than I want them to) and the amazing amount of xtracycle shimmy that the thing has when it’s heavily loaded, and it sounds like a recipe for getting a built-as-an-xtracycle frame and going from there.

But there are some problems with that:

Now the simple way of getting around that is to find one of the half-dozen-or-so framebuilding shops that will build cargo bikes. But that would put me back at least $2000, which is a lot of money for a frame. If I built one from scratch (either by buying a whole stack of lugs and tubes, then brazing them artistically together, or by taking a junker frame, chopping off the rear triangle, then buying enough tubes to make a somewhat longer triangle, it would not only be modestly cheaper, but at the end of it I would have had practice in how to build a frame (similarly to the front rack and rando bags I’ve made; I’ve spent about as much money on equipment and stock as it would have cost to buy a rack + bag, but I’ve made multiple racks and bags out of it and have gotten to the point where I can pretty consistantly make ones that work and don’t look hideous.)

There is the tiny detail of time and money, of course, but the whole idea of having a cargo bike that doesn’t trap my feet at random intervals is very appealing, as is the whole idea of being able to construct them myself.

Comments


From my rather limited understanding, the hard part with frame building is maintaining and checking alignment. This seems to require things like machinist’s surfaces and complex jigging (and sometimes milling machines) so things like the end faces of the bottom bracket shell being parallel to each other, flat, and parallel to the plane of chain in the drive train. This appears to be a much bigger investment in equipment than even five frames worth.

Graydon Thu Mar 17 14:22:04 2011

There are quite a few different sorts of jigs available for building up frames, ranging from simple rails up to metal plates with holes for clamping dummy axles and dummy bottom brackets to (and some people just weld their bicycles up freehand.) And I suspect that quite a few bicycle shops will face bottom bracket shells and headtubes (there are a lot of commercial bicycle frame venders who don’t do that, and any place where people repaint frames will need to have someone reface those frames so the paint won’t drive them out of true.

So the infrastructure (outside of the cost for a good set of brazing tools) doesn’t have to be too expensive.

David Parsons Thu Mar 17 16:34:02 2011

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