Originally Posted by
cyccommute
While there is a bit of heat loss through the metal parts of the bicycle, I think your experiencing more of a physiological response to the cold than a thermodynamic one. Feet and hands get cold due to decreases in circulation as the body pulls more heat to the core. The surface area to volume ratio is higher for your fingers and toes so you radiate more heat there as well. Add in shoes that fit tighter and gloves that fit tighter and everything starts to works against you keeping warm.
Also, the foot muscles don't get much exercise while cycling so that limits warming circulation vs while walking or running. Feet & esp toes can swell during cold, I read that some cold-weather bikers emphasize having a roomy shoe though I'm sure rhm has already thought about that. OTOH due to hard-to-fit feet I've been dealing w/inadequate winter footwear for decades so I'm semi-immune to the cold. Cold-numbed feet aren't fun but unless conditions are pretty terrible one won't get frostbite.
Well anyway I look now at posts about electric socks & chemical foot warmers--apparently not perfect solutions but might work for some bikers.