Gear ratios

[RogM]

Hi guys,

 

Please advise on the difference in final gear ratio including wheel size, on:

 

28 chainring, 36 sprocket, 29" wheel

36 chainring, 40 sprocket, 29" wheel

36 chainring, 42 sprocket, 29" wheel

36 chainring, 40 sprocket, 26" wheel

36 chainring, 42 sprocket, 26" wheel

 

Thanks

Rog

[FirstV8]

Use the ratio calculator 

 

http://gears.mtbcrosscountry.com/#26

 

 

http://www.bikecalc.com/gear_ratios

[PygaSchmyga]

Hi guys,

 

Please advise on the difference in final gear ratio including wheel size, on:

 

28 chainring, 36 sprocket, 29" wheel

36 chainring, 40 sprocket, 29" wheel

36 chainring, 42 sprocket, 29" wheel

36 chainring, 40 sprocket, 26" wheel

36 chainring, 42 sprocket, 26" wheel

 

Thanks

Rog

 

The math is quite simple - just remember FRONT OVER BACK.  Take the number of teeth of the front ring, and divide it by the number of teeth of the back chain ring.  From your list above, 28/36 = 0,77.  This means that for every full rotation of your pedals, your back wheel will only have a 0,77 rotation - ie about three quarters.  Next is 36/40 = 0,9.  This is a harder gear.

 

I guess that the same gear ratio on a 26' and 29' would feel harder on a 29', because you have a larger circumference on the 29', but I', not sure how the math would work

[DieselnDust]

The math is quite simple - just remember FRONT OVER BACK.  Take the number of teeth of the front ring, and divide it by the number of teeth of the back chain ring.  From your list above, 28/36 = 0,77.  This means that for every full rotation of your pedals, your back wheel will only have a 0,77 rotation - ie about three quarters.  Next is 36/40 = 0,9.  This is a harder gear.

 

I guess that the same gear ratio on a 26' and 29' would feel harder on a 29', because you have a larger circumference on the 29', but I', not sure how the math would work

 

 

You need to multiply by pi.D to get the rollout. the calculators posted above allow you to take that into account

[Spoke101]

Just download an app called Gearinchy, used to us it all the time when racing Track.

[RogM]

Thanks for the replies guys..