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Chain length/links calculator

4K views 5 replies 5 participants last post by  johnrude 
#1 ·
Searching the forums I found one old program that was built to run under WinNT (yikes!). Wonder if anyone knew of some more modern program (or web app).

TIA!
-AJ
 
#2 ·
AJL said:
Searching the forums I found one old program that was built to run under WinNT (yikes!). Wonder if anyone knew of some more modern program (or web app).

TIA!
-AJ
There probably aren't many because there aren't many reasons to have one. The normal methods for determining chain length (Shimano, Campagnolo, and SRAM instructions and any mechanic's handbook all have them detailed) are less work than trying to make the input measurements needed for a program accurate enough.

However...

For fixed gear, this is a resource:
http://eehouse.org/fixin/formfmu.php

Here is a more broadly useful one based on Javascript:
http://www.machinehead-software.co.uk/bike/chain_length/chainlengthcalc.html
 
#3 ·
You don't need a computer program, you can do it trial and error; big/big plus 2links (1") minimum.

Or you can do it using some simple math, 2x the on-center distance from cranks to rear axle, plus 1/2 the sum of the biggest chainring and rear sprocket, plus 2-4 links (1-1/2 - 2"), depending on rounding. Go high range if there's a large difference in the sprocket sizes, and low range if not.
 
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