IIRC the 8 speed 105 STIs are double/triple on the left side so you could probably run a triple without too much trouble. I like the sugino xd600 with 46/36/26 rings and an 11-28 or 11-32 gives me a crazy amount of gears with enough low gears to crawl up any of the hills I run into around here. I'm still a clyde so I find I need the lows more than most people seem to.