canging chainrings

thiscocks

Just a quick one:

Do you need to adjust the front or rear (if at all) derailleurs if you change say a 39 front ring to a 42? Haven't changed it yet but will do soon..

Cheers,
Tim

ride_whenever

Not if the ring you are changing is the inner one, but if you change your outer to a 42 from a 39 (god knows why) then you'll need to move the front mech up a bit, otherwise everything will work mech wise.

Also the chain will need to be lengthened if it's the outer ring.