Anyone use one of these?
http://ebay.com/
The following is what the Ebay seller says about the item:
This is a 2-speed gear withing your chainset! there is a button where the
crank dustcover is, tap it with your heel and you get direct drive. Tap the
button on the other side and you get a low gear (1:2.5 reduction, so the
50-tooth ring becomes an effective 20-tooth ring). Bolt circle is 110bcd;
single 50 tooth ring is fitted, but you can run double rings if you want.
See http://www.schlumpf.ch/
I'd be interested in reading whether others have used this or similar device and its reliablity. Never seen one before, though that doesn't mean much. There's a lot I have never seen.
Thanks.
Cheers.
Tom