chain length
 

Anyone know the Chain length for a sum of all parts 520 chain with 15/43 ?

Well the stock chain is 102 links, and stock gearing is 41/16

Given you are changing to 43/15, the run around the different sprockets is 1/2 a link greater (given the chain runs around 1/2 of each sprocket).

The pitch of the chain is 15.88mm, so with the stock 102 link chain, the axle would be sitting 4mm further forward with the 43/15 sprockets.

Or if you add another link (103), the axle would sit 4mm further back with the 43/15 sprockets.

Thank you , very good info

Actually, you can't add just one link; chains need to be in even numbers of links because there are alternating inner and outer links. If you used 104 links, the axle would be shifted 13mm back.