Current Projects chat and miscellany

Can't be too many people who've used that setup... :)

Yeah, I guess there are more or less half the teeth on the ring in contact with the chain at any time, although the angle of the chain to the sprocket must affect the tension a bit.

Yes In the end I found it slightly annoying on clean flat roads so I stuck a round 1/8 ring on when I built the Centurion

Sheldon said "A 42 tooth chainring will generally engage 21 teeth against 21 chain rollers, regardless of its shape.
There is a slight variation in tension resulting from the varying angle between the two straight runs of chain as the axis of the chainring rotates, but this has not generally been of a sufficient magnitude to cause any problem in practice for me".
http://sheldonbrown.com/biopace.html