Shimano mountain shoes. In the winter my toes used to get cold, but a few weeks ago I wrapped a plastic grocery sack around the toes and wrapped it in duct tape. IE hobo toe covers. My toes are fine now, it's been down to about 5*F.
At 0 or below, I usually install platform pedals and switch to hunting boots.
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Work: the 8 hours that separates bike rides.