best way to achieve a lower gear?
I am in need for a lower gear. I notice when climbing my buddies are able to climb with higher rpm and seated while I am grinding it out of the saddle. my front chain ring is a double 42t and 53t campy and my cassette is a dura ace 12-21 8 speed.
What is the easiest way to make a change? Change the 42t chain ring to a 39t or go with a 12-25 or 13-26? Would changing the rear cassette require a change in the chain where as the chain ring would not?