Icebikers are people who lack the common sense to stop riding when the weather turns cold. This can include people in Texas (apparently it does freeze there on rare occasion) and people in Alaska. It includes hipsters in rolled up jeans on their fixed gears and office workers slogging through slush on their Civias (or will be soon). It's the one kind of biking that breaks down all typical barriers because it is not defined by how or what a person rides. It is, however, a truly shared experience. There tends to be a rift between bikers of various types (people who hate spandex, people who hate geared bikes, people who hate people without helmets, etc.) just like in any subculture. When it's -10F outside, that rift simply disappears - you're all icebikers.
Because I've only ridden a few hundred miles this winter, I'm hardly an authority on the subject. I have, however, ridden in the full range of what Minnesota winters have to offer. My coldest ride this year was -17F with a windchill well into the thirties below; this was a clarifying experience. Being outside in the severe cold is not a matter of superhuman endurance or stupidity like most assume, but rather a matter of planning well. Any sort of aerobic activity will allow you to create all of the heat you need, but what's important is being able to trap that heat without sweating. Sweat makes you wet, and when you're wet the effectiveness of your insulation becomes compromised. When it's twenty below and you're an hour into your ride, getting tired and your tongue is beginning to get cold you really don't want your equipment to start failing. Layering different fabrics at different temperature break points becomes a precise science, so I'm going to detail the temperature ranges at which I use various equipment.
40° to 30° F
- Arc'teryx wind jacket (not sure what model - Arc never labels their garments for some reason)
- Light weight crew neck Smartwool shirt
- Riding shorts (MTB - they look like regular shorts)
- GORE Leg warmers
- Biking socks (short socks, basically), wool
- MTB shoes
- Cloudveil silkweight balaclava
- Arc'teryx wind jacket
- Light weight crew neck Smartwool shirt
- Light weight zip neck Smartwool shirt
- Performance cycling shorts w/ chamois
- Izumi AmFib bib tights
- Mid weight wool socks
- Lake MZ-302 boots
- Cloudveil silkweight balaclava
- Arc'teryx wind jacket
- Light weight crew neck Smartwool shirt
- Medium weight Icebreaker, Sport 320
- Performance cycling shorts w/ chamois
- Izumi AmFib bib tights
- Light weight wool slip sock, Smartwool
- Mid weight wool socks
- Lake MZ-302 boots
- Cloudveil silkweight balaclava
- Masque facemask
- Arc'teryx wind jacket
- Light weight crew neck Smartwool shirt
- Medium weight Icebreaker, Sport 320
- Performance cycling shorts w/ chamois
- Izumi AmFib bib tights
- Swiz or Ibex skiing tights (over the Izumis)
- Light weight wool slip sock, Smartwool
- Heavy weight wool socks
- Lake MZ-302 boots
- Cloudveil silkweight balaclava
- REI Polartech cap
- Masque facemask
- Goggles
- Arc'teryx wind jacket
- Light weight crew neck Smartwool shirt
- Light weight zip neck Smartwool shirt
- Medium weight Icebreaker, Sport 320
- Performance cycling shorts w/ chamois
- Izumi AmFib bib tights
- North Face snowboarding pants
- Light weight wool slip sock, Smartwool
- Heavy weight wool socks, Smartwool
- Lake MZ-302 boots
Civia Cycles has a good visual chart like this here. It doesn't exactly work for me, as I'm a warmer rider than normal and their recommendations rely too heavily on chemical heating pads for my taste, but it's generally very accurate.
Also, if it seems as though I really like Civia, it's more about my admiration for what they're doing. Reintroducing the bicycle as a high end utility vehicle is a great way to appeal to people who think that bikes are just for kids. Naturally, 98% of the population won't give a damn - no force on the planet will get them to ride to work no matter how nice the bike - but even getting that last two percent can make a huge difference.