Monday, March 22, 2010

The Electric Electra

This repair was interesting. I thrive on oddball requests, but sometimes bikes come in where one look sends me running the other direction. Sometimes, I don't run quite fast enough.

I got called down to do a brake adjustment on the bike, and immediately noticed that it had a hub motor, and that the axle was significantly larger than the 9x1 QR that the fork was designed to take. To make it fit, the dropouts had been filed out, and the torque on the anti-rotation washers had distorted them further (750W motor). The brake adjustment was needed because the wheel had slipped down in the dropouts, which I pointed out. I also recommended that we not do any further work on the bike unless the safety issues were cleared up.

The owner agreed, and we worked up an estimate for fixing most everything. The existing fork would have to stay, as there isn't a 26" fork with an extended threaded steerer that fits a 14mm axle currently available. The wheel could be spaced out to 100mm to fit the fork instead of the fork being forced to fit the 80mm hub. The rear rack had failed, and would have to be replaced. The rear wheel would be rebuilt with a new rim and spokes to take the weight of the rider and the battery pack.

I figured that this would take about a day of work and billed it accordingly, plus an allowance for parts. At the end of the first day I realized I'd made a bit of an error in the time estimate.

It took 2 trips to the local Ace, one for hardware to adapt the mount for the battery to the new rack, and the second to find 14mm, 1.5 pitch nuts to use as spacers on the axle. I designed and produced the mount, declared it fit for service and mounted the battery and the rack. This took a few pretty enjoyable hours of measuring, scribing and drilling 16 holes accurately with a hand drill. The results were worth it however, as it came out looking very nice, and is extremely sturdy. The front wheel was an entirely different can of worms.

There was a nipple that had come off rolling around in the wheel, it was horribly out of true, and the electrical connection terminated at the motor controller. To work on the wheel a good half of the electrical system had to be removed and the wires punched out of the molex-style connector (to pass through the 14mm nut). The front wheel took more than a few hours of work, and although it tickled my problem solving side, the design is incredibly heinous.

The second day was spent building the rear wheel (fun), and putting everything I'd taken apart back together (frustrating, due to the poor design). All told, I spent 15-20 hours on this one repair. At the end of it I was confident that it would hold up to any reasonable road ride.

When he picked up the bike, I found out that he'd been riding an incredibly heavy and overpowered bike over curbs. Which perhaps explains why everything was destroyed.

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