Difference in gear ratios?

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06-19-19, 02:23 PM

#26

Bandera

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No such thing as concerns about "extreme combos" when one only has a single chain-ring and cog, although getting chain-line correct is quite important on a fixed gear as is chain tension.

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xroadcharlie

07-01-19, 08:37 AM

#27

estudiante

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Quote:

Originally Posted by mickey85

Hey all,

I have kind of an academic question...

Let's assume you have a bike with a given set of wheels, cranks, and tires. Is there any difference in gear ratios, if the gear inches stay close to the same? So, for instance, 40x15 and 48x18 are both 72 gear inches (or a gain ratio of 5.4). Is there any functional difference between the two setups as far as acceleration and braking ability?

Sheldon brown says bigger chainrings have slightlyless friction, less chain tension and longer chain/sprocket life but they are slightly heavier and chainstay clearance may be a problem on some frames. On the other hand Smaller chainrings are slightly lighter and have more chainstay clearance, with the downside of Rapid chain/sprocket wear and greater chain tension (increased likelihood of the axle's slipping in the frame)

I think if chain tension increases acceleration may be negatively affected “slightly”

I feel like that when i am adjusting the chain tension during tyre change. I may be wrong of course.