Gear Ratio to wheel travel- Mtbr.com

# Thread: Gear Ratio to wheel travel

1. ## Gear Ratio to wheel travel

Ok maybe I'm dumb (probably) but if I run 32:16 and 34:17 it is still a 2:1 gear ratio. But this is my question is the travel of the bike, ie. distance on the ground I move in one pedal revolution the same? I know this is a newbie question, but hey I'm burnt so work withme here. Cause if it isn't then it would reason to make sense to run 34:17 versus 32:16 or is it easier on 32:16.
Ok simplify the question, why would one run 34:17 versus 32:16?
thanks
the capt.

2. Originally Posted by Capt_phun
Ok maybe I'm dumb (probably) but if I run 32:16 and 34:17 it is still a 2:1 gear ratio. But this is my question is the travel of the bike, ie. distance on the ground I move in one pedal revolution the same? I know this is a newbie question, but hey I'm burnt so work withme here. Cause if it isn't then it would reason to make sense to run 34:17 versus 32:16 or is it easier on 32:16.
Ok simplify the question, why would one run 34:17 versus 32:16?
thanks
the capt.
the gear inch, ratio and travel is the same for those 2 configurations. the only reason for running the 34:17 would be that it wouldn't wear as fast as the 32:16.

there's a nifty java gear calculator at chainrings.com

3. ## Same-o, same-o

Originally Posted by Capt_phun
Ok simplify the question, why would one run 34:17 versus 32:16? thanks the capt.
The gear ratio is the same, therefore the distance traveled will be the same.

One good reason to use a larger ring and larger cog is that the larger equipment will wear ever so slightly slower. Chains, cogs and rings are expensive. Alternately, the larger equipment weights ever so slightly more.

--Sparty

4. ## Not al 2:1 are the same

Originally Posted by Sparticus
The gear ratio is the same, therefore the distance traveled will be the same.

One good reason to use a larger ring and larger cog is that the larger equipment will wear ever so slightly slower. Chains, cogs and rings are expensive. Alternately, the larger equipment weights ever so slightly more.

--Sparty
It's a bugger of a math problem, but low and behold there are mechnical advantages to running a larger 2:1 than a smaller one (i.e 40:20 vs. 32:16). It has to do with the distance of the drive and lever arm from the point of rotation (BB spindle). Ask any mechanical engineering prof and he could probably explain it better than I. In practice the improved output (watts) from the same input (pedal stroke power) using a larger 2:1 is probably negated by the increased weight of the larger rings and longer chain. Dave

5. Originally Posted by Gearless Dave
It's a bugger of a math problem, but low and behold there are mechnical advantages to running a larger 2:1 than a smaller one (i.e 40:20 vs. 32:16). It has to do with the distance of the drive and lever arm from the point of rotation (BB spindle). Ask any mechanical engineering prof and he could probably explain it better than I. In practice the improved output (watts) from the same input (pedal stroke power) using a larger 2:1 is probably negated by the increased weight of the larger rings and longer chain. Dave
2:1 is 2:1. The only "mechanical advantage" of the larger 2:1 is that it is slightly more efficient (and some can even tell the difference in terms of smoother pedaling). You will require very slightly less effort to go a given distance, but it will still take the same number of crank revolutions to achieve that distance.

- Dan

6. Quote:
<TABLE cellSpacing=0 cellPadding=6 width="100%" border=0><TBODY><TR><TD class=alt1 style="BORDER-RIGHT: 1px inset; BORDER-TOP: 1px inset; BORDER-LEFT: 1px inset; BORDER-BOTTOM: 1px inset">Originally Posted by Gearless Dave
It's a bugger of a math problem, but low and behold there are mechnical advantages to running a larger 2:1 than a smaller one (i.e 40:20 vs. 32:16). It has to do with the distance of the drive and lever arm from the point of rotation (BB spindle). Ask any mechanical engineering prof and he could probably explain it better than I. In practice the improved output (watts) from the same input (pedal stroke power) using a larger 2:1 is probably negated by the increased weight of the larger rings and longer chain. Dave </TD></TR></TBODY></TABLE>

Originally Posted by GlowBoy
2:1 is 2:1. The only "mechanical advantage" of the larger 2:1 is that it is slightly more efficient (and some can even tell the difference in terms of smoother pedaling). You will require very slightly less effort to go a given distance, but it will still take the same number of crank revolutions to achieve that distance.

- Dan
I wonder if you guys are saying the same thing.

--Sparty

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