[UPMICHAEL]

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<><

 

[C-40]

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.