I live in a very hilly area, there is no flat ground to ride on and the hills are *very* steep. My triple 48-38-28 is way too big for my use. I never use the big chain ring. I use the 38 a little but spend most of my time on the 28 (with a 34t in the back). My question: I'm thinking about getting the Sugino Impel triple which has 42-34-24t rings (I wanted the 42-32-22 version but it only comes in size 175mm and the 650B wheels on my early 80's Specialized Sequoia frame won't allow anything longer than the 170mm cranks I have now). Is the 42-34-24 the lowest gear combo possible for me? Or should I just strip off the 48t on my current cranks and replace the 28t with a 24t and ride a double? If so, how would I know what size Bb to use? Thanks for the info!