Gearing ratios: 650 vs. 700

Triathlon Forum
1

I was training for the Grand Columbian half the other day, going up the Almira grade on my 700c road bike with a 39 x 27, which seems a capable gear.

Any idea how that translates to a 650c wheelset with a 42 front inner chain ring? I’ll be riding it again on my 650c tri bike before the race, but anyone want to take a guess?

2

You don’t have to guess:
http://www.sheldonbrown.com/gears/

You can figure out any gearing combo you want.

3

I’ve found that you’ll get basically equivalent gearing by going up 2 teeth on the chainring when going from 700s to 650s.

4

700C 39X27 is 120 gear inches or 10.23 mph at 90 rpm

650C 42X27 is 119.4 gear inches or 10.18 mph at 90 rpm

Allmost the same gear

jaretj
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