Help figure out gear ratios

Wildcat · May 25, 2016

I have a bad cog that's bent and I need to figure out how to change out either the cog, or chain wheel if I can't get the right size cog. I want to keep the same ratio or make it slightly easier to pedal (lower ratio?).

It has a 44 tooth chain wheel and a 22 tooth cog. If I put the original 19 tooth cog back on, what number of teeth does the chain wheel need to keep it nearly the same or lower? I can get a 36 or 40 tooth replacement for the chain wheel. What will work best?

horsefarmer · May 25, 2016

Is now:
44tooth/20tooth=2.2 wheel revs per crank rev x 26"=57 gear inches
options:

slightly lower gear
40tooth/19tooth=2.1 wheel revs per crank rev x 26"=55 gear inches

quite a bit lower:
36tooth/19tooth=1.9 wheel revs per crank rev x 26"=49 gear inches

Wildcat · May 25, 2016

40 it is!

deorman · May 25, 2016

Lazy man's way, for future reference.
http://www.bikecalc.com/gear_inches

Bicycle808 · May 25, 2016

horsefarmer said:
Is now:
44tooth/20tooth=2.2 wheel revs per crank rev x 26"=57 gear inches
options:

slightly lower gear
40tooth/19tooth=2.1 wheel revs per crank rev x 26"=55 gear inches

quite a bit lower:
36tooth/19tooth=1.9 wheel revs per crank rev x 26"=49 gear inches

This is good, except in the OP, he says the current ratio is 44x22, which is 52" on a 26" wheel. Going to a 40x19 would actually increase the ratio by 3 gear inches. A 36x19 would decrease by 3 gear inches.

Wildcat · May 26, 2016

deorman said:
Lazy man's way, for future reference.
http://www.bikecalc.com/gear_inches

Then that's the way I'll do it, the lazy way! :dance2:

Thanks for the link to that calculator.

That answered my questions, and depending what size chain rings and cogs I can get, I'll try to get as close to 50 gear inches as I can. right now, with my 44-22, it's 52.5,
At 40-19 it's 55.4, too high

36-19 is just about right, 49.6. A small chain wheel is what I'm shooting for. Too bad I didn't bring a lucky 7 with me when I moved.

Second gear is 135% of that, so that will be 67 gear inches, just about the same as 46-18, a good cruising gear.