My vintage bike has a Shimano 105 Biopace 52/42 crankset with a 12-28 cassette. I love the way it feels when I pedal, the biopace chainrings are great, for me. The 52/42 combination is fine for where I live and ride here in the Houston area, but I intend to spend all of next summer in southern Maine where it is much more hilly, my lowest gear of 42-28t will kill me. I wonder if it would be possible to purchase a used Biopace 48-38-28 triple and somehow convert it to a 48-28 double. Would anyone suggest what some options to a few lower gears might be? Thanks for any help!