Dang, beat me to -30f this year. We have dropped that low but I didn't get the opportunity to ride in it yet.
Thanks, but we DID wait for it to "warm" up to minus 12 before setting off, and......it was back down to minus 15 when we finished.
Now, a question for you, I've always found the difference in clothing between -10 and -30 to be fairly minor when on a bike. I use the same puffy and vest, they just get fully zipped up instead of partially unzipped. Mainly cover more of the face and make sure the chemical heat packs are working. How did you find it?
I don't think I have a lot to offer here. I normally cut things off at zero or minus 5, but my buddy was heading back to TX and really wanted to squeeze in one more ride before heading back to "real" life. So, with that long-winded caveat, when it's really cold by my standards:
1. Warm biking-specific bib knickers, with an old but trusty pair of North Face Gore something or other tights. I have PI Amphib tights, but have concluded they are too warm for anything active.
2. Light wool base layer, overlaid by medium wool sweater.
3. Puffy down sweater. Not quite jacket weight. Zipped going down, unzipped going up.
4. A Seirus magnetic face mask that lets me easily pull the mag part down for nose blowing and slower climbing. At 65, I've frozen my face too darn many times, and don't want to do it again.
5. Cheap, but serviceable Zeal goggles with the foam torn out of the top vents so they breat better. Beat to hell Anon goggles with all the foam if it's snowing.
6. Some kind of Castelli gauntlet gloves that use -fancy synthetic insulation (gold something or other?) that is far warmer than its lack of bulk would suggest. Electric ski gloves get too warm.
7. Bontrager Old Man Winter Boots without the felt liners, instead opting for wool insoles, and two layers of thick, cheap Carhartt socks.
Hope that helps!