Space between botton bracket and crank arm
07-04-13, 01:00 PM
#1
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Space between botton bracket and crank arm
Hi guy
my BF NWT got a Rohloff again.For me the the space between the botton bracket and the crank is a little be wide .What do you think the guy on the bike shop told me must be like this because of the chain line.The gears are working perfect just compare to my wife bike the space is no so wide my bike is 0,5cm each side wider
my BF NWT got a Rohloff again.For me the the space between the botton bracket and the crank is a little be wide .What do you think the guy on the bike shop told me must be like this because of the chain line.The gears are working perfect just compare to my wife bike the space is no so wide my bike is 0,5cm each side wider
07-04-13, 02:19 PM
#2
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Yup, Its like that to get the Chain line right, it has to be 54mm BTW, thats Spec.
My Bike FridayPocket Llama [R'off, disc], now has a 125 wide BB axle ..
if you had a low profile Crankset, then the crank arm comes in to meet a shorter spindle.
but the chainline of the chainring has to remain the same.
My Bike FridayPocket Llama [R'off, disc], now has a 125 wide BB axle ..
if you had a low profile Crankset, then the crank arm comes in to meet a shorter spindle.
but the chainline of the chainring has to remain the same.
Last edited by fietsbob; 07-04-13 at 02:25 PM.
07-09-13, 06:46 AM
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I recently built up a non-folding touring bike with a Rohloff. I bought a cheap double crankset, crankset manufacturer recommended a 110mm bottom bracket spindle (square taper), I assumed that recommendation was for a road bike with 130mm rear spacing.
I used a 122.5mm bottom bracket and am using the chainring on the inner position with a chainguard (bash guard) on the outer position.
My calculations told me that I needed an even longer bottom bracket but I wanted my Q factor to be no more than a half inch wider than on my derailleur bikes.
https://en.wikipedia.org/wiki/Q_factor_%28bicycles%29
Thus, I have a chainline that is about 5mm off.
I used a 122.5mm bottom bracket and am using the chainring on the inner position with a chainguard (bash guard) on the outer position.
My calculations told me that I needed an even longer bottom bracket but I wanted my Q factor to be no more than a half inch wider than on my derailleur bikes.
https://en.wikipedia.org/wiki/Q_factor_%28bicycles%29
Thus, I have a chainline that is about 5mm off.
07-09-13, 10:36 AM
#4
Banned
R'off suggests, in retrofits , place the drive chainring on the Outside where the Big Ring sits..
as the OP has done..
(use spacers to put chainguards, on the outside, then)
longer the chain-stays the less it matters, on Recumbents, with a very long ways
between crank and hub, it does not matter at all ..
as the OP has done..
(use spacers to put chainguards, on the outside, then)
longer the chain-stays the less it matters, on Recumbents, with a very long ways
between crank and hub, it does not matter at all ..
Last edited by fietsbob; 07-09-13 at 10:41 AM.
