# Chain wrap capacity



## UPMICHAEL (Sep 1, 2003)

I've checked several websites. But can not find one on how to calulate wrap capacity for rear derailleur. Anybody know a website or can tell me how to do it? Michael<><


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## C-40 (Feb 4, 2004)

*wrap capacity...*

The wrap is just the difference between the number of chain ring teeth plus the difference between the cog teeth. For example a 53/39 with a 12-25 cassette requires 14 + 13 = 27 teeth of wrap capacity from the RD.

As for the capacity of the rear derailleur it should be listed in the manufacturers literature. It can't be calculated.


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