Swapping out cassettes- adjust deraileur/chain length?
Hi there. I recently purchased a pinarello that came with "junior gearing" (14-25 I believe). I want to swap out the cassette for an 11-25. Does this require the rear deraileur to be adjusted, or to change the length of the chain. Since the highest gear remains the same, I don't think so, but just want to confirm.
Just remove the chain and move the derailleur by hand back and forth to see the spacing between the cogs and the guide pulley (the one closest to the cogs). Adjust by turning the B-screw. You normally want that around 5-10mm from the cogs to the pulley at its closest point depending on manufacturer (I set based on the big cog with an 11-25/28 and SRAM). It can be checked and set with the chain on but it's a lot easier without.