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Discussion Starter · #1 ·
Once upon a time I stumbled upon this table on the Internet.

Text White Line Colorfulness Style


Can someone explain to me how is chainline measured for single speed cranks, especially for Truvativ ones (like Isoflow, Fived, Hussefelt)? Is it measured for the only ring on the crank and if not, what is the distance between the chainline measurement plane and the only ring?

Sheldon Brown gave examples for triple and double cranks only: http://www.sheldonbrown.com/chainline.html

I'm asking because I need to set up a perfect chainline for the single rear sprocket using one of the Truvativ single speed cranks and I'm wondering which bottom bracket (in terms of spindle width) to use. Thanks in advance.
 

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From your link there it says "Chainline is measured from the centerline of the frame to the center of the chain." So if you only have one ring you would measure to its center. Are you using a bmx style freewheel or spacers/ring on a splined hub?
 

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Discussion Starter · #3 ·
cackalacky said:
From your link there it says "Chainline is measured from the centerline of the frame to the center of the chain." So if you only have one ring you would measure to its center.
But is it also the case for Truvativ single speed cranks? Can someone confirm this? Cause this would mean that the only ring on their single speed cranks is in the same distance from the frame centerline as is the middle ring on a mountain triple.

If this is indeed the case, then, considering what spindle length they offer on their bottom brackets, I cannot use them.

cackalacky said:
Are you using a bmx style freewheel or spacers/ring on a splined hub?
Neither, the rear sprocket is immovable. I need to have 54 mm chainline but would also like to configure it using one of the Truvativ cranks with a 38 teeth ring to get preferred ratio.
 

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As the others have said, it's to the middle of the chainrings.

for singles, it's obvious
for doubles, to the middle of the space between them
for triples, to the middle chainring.

BTW- the easiest way is to measure from the chainring to either the seat or down tube, and add 1/2 the diameter of the tube.
 
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