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?

studded tires are nice, but the one single bike upgrade that i've made over the past several years that has propelled my enjoyment of bike commuting (and cycling in general) to stratospheric levels is clipless pedals. i just love them so dearly; i can no longer ride a bike without them.

Do the studs take damange if it's dry? (I.e. mixed weather with patchy slicks and lots of dry pavement.)

How about slush?

It's good hearing from someone who's braved the slick weather. I haven't yet.

Christofoo: The Nokian's (as well as some other brands) have carbide studs, so no they don't wear down on the pavement. This is the time of year when they really shine. It's always a mixed bag of dry pavement, sheer ice, packed snow, slush, frozen slush, puddles, half frozen puddles, and mud, and you can encounter any or all of them in any given 300 foot stretch. Treacherous yes, but they make it possible.

Puncture resistant tire. Without them, I won't even commute by bike.

Full coverage fenders. Everytime I bought a new bike, fenders was the very first upgrade I did.

bicycle

I got a Neon lime rain parka with wide reflective strips on it.
just wish they made the Hood as part of the thing, like a Mountain parka,
not a stow in the collar type thing..

My pump.. because if my tires are low it's harder to pedal and that's no fun.

My handlebars. Without handlebars, commuting by bike would be no fun.

Definitely tires.

I almost never have to deal with ice, so I don't use studded tires. For me, it's tires that provide good puncture protection and grip but still feel lively. The difference between good tires and bad tires makes an enormous impact on how much I enjoy the ride, even if they aren't going flat. I've had several tires I liked a lot and several that were not so fun. I just got some Conti GP 4 Seasons that I'm loving right now.

Rear rack. It allowed me to carry essential items like food and repair stuff's.

I'd also have to say tires; I change out tires when the temps drop, as I know the snow won't be far behind.

This year, I went with a set from "across the pond" -- DMR Redshift (26x2.25), which have an aggressive tread pattern like the Maxxis Ignitor, but seem to roll better for me. VERY LITTLE slippage in the slop.....

They've worn well, too, so when I pull them off next week, I can hang 'em and save 'em for next winter!

2nd on the list would have to be lights; strong blinky tail lights make it a lot tougher for drivers to "not see me".

my bibs.

Take a Look mirror, to keep motorists off my elbow.

W106's - fenders are close, very close, but I could still ride without fenders. Without the W106's, put the bike away in November, take it out in April. W106's for the win.

Haven't gotten it yet, but I'm going to say a IGH. My derailleur is getting too banged up on my multi-modal commute...

Actual bicycle clothing. After getting used to all the lyrca, I just feel foolish riding a bike in regular clothing.

It's funny you mention that because I definitely encountered plenty of icy bumps on the road today. Was very happy for my studded tires.

I know people that say they don't help much but it's days like today that they really shine.

I think that mirror saved my bacon at least once.

Toss up between a mirror and Dinnotte tail light.

Dyno hub and light is up there for me. Nice not to have to worry about batteries.

I'm also really happy with my Pearl Izumi Gavia jacket. Keeps me comfortable from below 0F to about 50F.

Paul

For commuting in the dark:
Lights
Puncture resistant tires
Saddle

For commuting in the light:
Puncture resistant tires
Saddle

1+ Once you have a Dinotte 400R, it doesn't seem safe commuting in the dark anymore with the usual AA battery powered LED's.

Try a unicycle commute