Maths/Gear ratio question...

TheBullet

HI,
I was wondering, is there an optimum ration of gears for efficiency? For example (this is just an example so not technically correct) say a 39/25 was the same distance for 1 revolution as a 34/21 would one of them need less power to move that distance i.e. turn the crank 1 revolution?

Hope that makes sense but I have looked on the internet and not found an answer.

Anonymous

Gear inches is gear inches...

Use this calcilatifier here -

http://www.sheldonbrown.com/gears/

Pokerface

Or you can use the equally accepted 1 gear inch = 2.54 gear centimeters.

Does that mean gear inches is more efficient? LOL

rolf_f

Pokerface wrote:

Or you can use the equally accepted 1 gear inch = 2.54 gear centimeters.

Does that mean gear inches is more efficient? LOL

I prefer gear chains myself - seems more fitting

1 gear inch = 0.00126262626 gear chains

jibberjim

There's a tiny efficiency improvement from larger rings due to the chain having to move less, but it's really irrelevant unless you're going for the hour record or something where such tiny changes might make a difference.

In road riding getting the actual gears you need will be more important.

TheBullet

There's a tiny efficiency improvement from larger rings due to the chain having to move less, but it's really irrelevant unless you're going for the hour record or something where such tiny changes might make a difference.

In road riding getting the actual gears you need will be more important.

Thanks jibberjim, I guess that was the answer I was looking for.

I ask because my new bike (purchased at the beginning of the year) has a compact and I have gone from riding a 54/39-12/23 to a 50/34-12/25 and after a full season riding I generally feel slower on the hills than last year. I know this could be a lot of different factors but that is why I asked.