# Rolhoff, road crankset and chain line



## Denis (Jan 7, 2004)

I am in the process of building a lightweight hardtail with a Rolhoff hub and I am looking for a crankset.

I have a couple of questions.

*Chain line*


Rolhoff recommends a 54 mm chain line (58 with a 13 teeth sprocket - not sure why)
A MTB crankset has a chain line of 47.5 to 50 mm according the Sheldon-Brown.
Does this mean that to get a correct chain line you have to use the outboard ring position?

*Road cranks*

I might have a killer deal on a lightweight road crankset. Does anyone have any experience with using a road (compact) crankset on a MTB and / or with a Rolhoff hub:


Durability (I am 185 LBS, do only XC, no jumping)?
Chain line?
Other?

Thanks.

Happy trails.


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## Denis (Jan 7, 2004)

Bump... (no response????)

I actually bought a MTB crank, so I am just wondering what people do about the chainline and where they mount the ring (middle / outside).

Thanks.


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## pursuiter (May 28, 2008)

If I had a frame with a 68mm BB, I'd purchase a 68/73mm BB and use two washer on the crank side, that will give the largest chainline possible. The outer ring will be 50mm or a little higher.


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## rockyuphill (Nov 28, 2004)

With a typical 48-50mm chainline MTB crank the outer ring chainline is pretty close to 54mm to 58mm chainline you need for a Rohloff (13T cog needs 58mm)

http://www.sheldonbrown.com/chainline.html#standards


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## pursuiter (May 28, 2008)

With my Shimano Deore LX cranks, 68mm bb, 68/73mm combo LX BB, with two washers on the chainring side, my middle ring CL is 50mm. 

edit: remeasured, you guys are correct. Is the Alfine hub 47.5mm CL with the cog flipped outie? That's what I'm measuring. Looks like I should move one of the washers over to the non-drive side.


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## nicolap99 (Mar 21, 2006)

I've got a Nicolai Helius CC with the FR rear triangle. The bottom bracket shell width is 68mm, and I'm using a Shimano XT Hollowtech crankset.

I'm using a Rohloff Speedhub - so the conventional method of mounting the 38T chain ring in the outer position should give me a 54mm chain line. (Using two 2.5mm spacers on the drive side , and one 2.5mm spacer on the non drive side.)


I've measured the chain line from the centre of the downtube to the centre of the chain ring, and found it to be greater than 54mm , more like 57mm.

To correct this, I've now set up the crank with one 2.5mm spacer on the drive side and two 2.5mm spacers on the non driveside.

Chainline looks to be better by eye, although I couldn't detect any difference when riding.


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