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?
Shift to large-large and see if you can pull a little slack in the bottom run. If the derailleur pulley is pulled as far as it can towards the cranks, then you need a longer chain, but if it's like most bikes, the chain probably has a couple extra links to cope with the larger sprocket.
