On Mar 6, 12:49 pm, Dan Connelly
wrote:
James Fitch wrote:
Does anyone know, offhand, what the outside diameters are of 53, 52, 51, 50
tooth chain rings? I'm fine tuning a derailleur fit. I'd like to get the
tail of the derailleur dropped a couple of mm to keep the chain from
dragging one rear cog smaller than it does now (currently 53 on the front).

-Jim

Each tooth is a half-inch. Diameter = circumference / pi.

Dan

Plus a skosh for the points of the teeth. The formula you posted
describes the diameter through the pins of the chain- the chainrings'
actual diameter is a little larger than that.

In my experience, fine-tuning front derailleur fit is best done once
the bike is completely assembled. If you need a front derailleur with
a longer cage, maybe you should indicate what kind of frame and front
derailleur you have currently.

Jeff