am i right in thinking:
26" wheel has a circumference of 207cm
the 11/34 will give 3.09 rotations per pedal stroke/crank rotation
there fore 6.4m?
You look correct so far.
This means that at 90rpm cranking you are doing 21.5mph
More than enough for flat tarmac.
PaulD
cool 🙂
34/11 on 26'' wheels is 80.3GI, probably a little high for general riding?
Pretty much spot on ^
34 x 11 on 172.5mm crank arms with a 26 x 2.25 tyre gives a gear inch of 83.4 = 6.65m for every revolution of the cranks
Not worked out in my head nor am i a gear inch bore - I used the Bike Gears app for the iPhone, pretty nifty little app that is one of the few apps i continue to use - especially in the bike shop.
I can't see what crank length has to do with it.
Neither can i avdave2? so here....have this award
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If i mentioned Gain Ratio then i guess it would have been relevant but seeing as i didn't?....hey ho.
The original poster did not mention what crank length he was using so as most folk either use 170mm or 175mm i thought i'd be a smart arse and use 172.5 to give a median gain ratio result but as i didn't bother including the result in the above post i guess this entire explanation has been pretty irrelevant so far - fwiw the gain ratio is 6.15 so for every inch the pedal rotates around the bottom bracket the bike will travel 6.15" forward.
A long way if its pointing downhill,
Thank you Somafunk I have saved it with my collection of gold stars I have for eating all my tea. 🙂
Well thought through; this is why I argue that very few people need a bigger gear than 34/11 or even 32/11 for anything other than road riding.
What would be the answer if on a 29" wheel ?
24.11mph
No bother avdave2 🙂 , i gave myself a special "there - there" pat on the head for my cock-up regarding gain ratio.
As for the 29"? :
34 x 11 on 172.5mm Crank arms running a 29 x 2.25 tyre gives a gear inch of 89.1" = 7.11m for every revolution of the cranks with a gain ratio of 6.58
The only difference crank length will make is how far your shoes travel. Hrumph! 😉