Hello, I am currently running a standard chainring set of 39X53 and would like to convert over to a TT setup and use 42X55. Will I need to install a longer chain for this TT ring set?
Buy the new chain. Is the old chain pitch within specification?
Install the new chain rings. Put the chain on the large chain ring and gently try to shift to the largest cogwheel in back.
To size a broken chain put the chain on big-big but not rove through the derailleur. Bring the chain ends together and allow one link (1 inch) extra.