I read earlier today that a group of college students were trying to design a bicycle for use at the South Pole. Early on they found that a single speed bike was the way to go. Too many plastic and metal parts on more complex bikes were breaking in temperatures that averaged -78 F. Single speed, under 20 inch rims and close to 7 inch tires. University of Pittsburgh I believe. They started with a MTB donated by an LBS in California and remade it as a Carbon fiber bike. Possible most bike alloys get brittle at -80 to -100 F. Anyone out there hear any more about it?