Chain length for new ring?
05-13-20, 06:15 PM
#1
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Chain length for new ring?
Hey all. I sized down my cog from a 18 to a 16 and am about to size up the ring from a 46T to a 48T. The rear axle has about 1.25-1.5 inches of travel available. Does anyone know the calculation to figure out if I need a longer chain to accomodate?
Thanks!
Thanks!
05-13-20, 06:17 PM
#2
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You come out to the same number of teeth in the end, so you shouldn't have to change anything in theory.
05-13-20, 06:26 PM
#3
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sounds good to me, I didn't know if the difference in diameter of ring v cog would have a greater change with addition/removal of teeth...
05-14-20, 01:12 AM
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The circumference can conveniently be measured in terms of teeth rather than inches or centimetres.
So you've added 2 teeth at one end and taken away 2 at the other, so the chain remains the same length — with a very slight adjustment to the position of the wheel because the top and bottom lengths of the chain are not parallel, and the angles have changed slightly.
05-16-20, 12:16 AM
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The fact that adding X teeth at one end and subtracting X teeth at the other end results in no change to the chain length can be really useful. Every winter, I change to a lower gear to cope with snow and studded tires, and just keep running the same chain. 
