The one piece of gear that has the biggest positive effect on the commute.
As a year round rider in a place with a brutal climate there is ONE thing that makes it all possible more than any of the others.
Studded bike tires. (Nokian W106 in my case)
Without them I'd be on my arse, in the hospital or I'd be driving the car. I just needed to sing their praises once more after surviving yet another icy sketchy morning upright and intact.
what's yours?