Tuesday, 6 July 2010

Brompton wheels

I have built quite a few Brompton wheels in the last couple of years.

Front: standard Brompton hub but with the original caged bearings thrown away and replaced with loose balls. Built radially like a factory one. No, the valve isn't very straight.

Front: Schmidt SON-XS dynamo hub. Not as expensive when I bought it as they are now. I'm not especially keen on the standard SON 28 for larger wheels, which is heavy, bulky and expensive compared to the latest Shimano alternative, but the XS is very light and compact.

Rear: 1970s Sturmey-Archer AW 3-speed hub. Runs in oil, very reliable and versatile. This has been up one of the highest road passes in England. Ratios of -25%, direct and +33%. Gives gearing of 45", 60" and 80" with 52 x 14. Velox 10mm rim tape works a lot better than the blue factory stuff, which doesn't actually fit the rim, causes pinch punctures and makes tyres nigh-on impossible to fit.

Rear: 1960s Sturmey-Archer FW 4-speed hub. Not actually tried this one yet, since I rebuilt the hub and built it into a wheel while the frame was away for respray. Yes, I have a 4-speed shifter (also works for 3-speed). Uses a special two-piece indicator spindle. This hub was probably for a Moulton originally. Ratios of -33%, -25%, direct and +25%. Gives gearing of 40", 47", 60" and 75" with 52 x 14. Decided to interlace the spokes on this one; Brompton wheels aren't normally interlaced but no-one knows why.

Rear: Looks like a modern S-RF3 but it isn't. It's a homebrew mashup of a 1948 AM, some AW parts and the S-RF3 shell. Uses a special two-piece indicator spindle, although can be converted to use a cheap and easily-available AW spindle by replacing the clutch key inside the hub. Oil-lubricated and wonderful to ride as long as there aren't any mountains. Ratios of -13.6%, direct and +15.5%. Gives gearing of 52", 60" and 69" with 52 x 14.

1 comment:

  1. It interesting blog. It would be great if you can provide more details about it.
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