Gearing question... check my math?

[-BB-]

Ok...
i'm trying to figure out if one setup will have a lower gear than another.

The setup

#1) 22 front; 30 rear; 24in tire

#2) 22 front; 34 rear; 26in tire

Here's what I did... tell me if I'm off.
First, you see how far around the rear cog goes for each pedal stroke

22/30 x 24 = 17.6

22/34 x 26 = 16.8

Result? The 26in w/ 34 cog climbs better.

Now if I wanted to get an exact distance traveled per (pedal)revolution, then i'd multiply the above numbers by 3.14, right?
(22/30 = % of 1 wheel revolution)
Wheel size = diameter
Circumfrence = diameter(3.14)
Multiply the two , and you get distance traveled in one pedal revolution.

17.6(3.14)= 55.26in/pedal
16.8(3.14)= 52.8in/pedal


Anyone see any flaws?

[mrbigisbudgood]

The only flaw I see is I would measure the actual circumfrence of the tire in question for more accurate results. Tire size will change the equation.

First.......find your front to rear gear ratio.

# teeth front/# teeth rear=ratio

22/30=.73333333333

22/34=.647058824

Now, find your forward motion per revolution

gear ratio X mesured circumfrence = forward motion per pedal stroke.