My situation. Got bad knees, a road bike, a commuter (LHT). Pedal fast, stay in smaller chainring, never the large chainring. Even with a larger cogset, I still run out of gears on long/steep hills on the road bike. Want to make my road bike gearing more like my Surly Trucker to make it more knee freindly. Road bike is a 15 yr old specialized with Shimano 105 8 spd STI with an older xt rear derailer.
My question. Getting a larger cogset is pretty strait forward, but getting smaller chainrings is not. I would like to keep the crank arms as they fit the bike real well (old as sht) and it would seam to be cheaper to keep the crank arms. Is there anyway to replace the 39/53 combo with 36/48 combo without replacing the crank arms???