Bike Gearing

David Matusow <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

I am curious to get some opinions on bike gearing for triathletes. I
currently have a 53-39 double on my Cannondale bike. I am thinking of
upgrading the components, and am trying to figure out if I should change
the gearing. Can someone please explain the details of the gearing
ratio?> --David

<<Snipped by rsquared>>

You are the foremost expert on what gearing you like but, I think the
question is, "How many inches does the bike travel, with one full turn
of the crank?"

In the U.S., I think the term is "gear inches", but few recreational
cyclists that I know quibble over that - - except fixed-gear riders.
I don't think most even know; they go by a relative tooth-count

Anyway, consult a chart. You may be able to find one on
www.sheldonbrown.com.

This formula is crude, but it gives you a sense of relative gear
inches - - I think:

[Gear Inches] = [No. of Teeth Engaged on the Front Ring]/[No. of Teeth
Engaged on the Rear])*27

The last time I used this is when I had 27" wheels. That is where the
"27" comes from. Close enough?

If nothing else, it gives you a sense for how much redundancy you have
in your gearing.

rsquared