Critical difference between 15 and 25 degrees F?
 

Good evening!

So I just registered in order to seek (hopefully) quick opinions or warings about riding the way I do these last months, best if any can relate what they've experienced.

Is there a critical (reasonably life-threatening, if that's possible to judge) difference between 15 and 25 degrees, as I am thinking of doing tomorrow morning at the colder what I did this morning when warmer?

- I rode in bike shorts (always with underwear in winter, sure still crazy but I've done it down to 24 without feeling cold overall.
- My upper body counts to me infinitely more, so at 25 wore thermal compression layer with thermal under shirt (both long-sleeved) and two non-thermal compression shirts on the inside, finally on outside a tight jersey for the pockets. As with uncovered legs, this part did not feel cold also.
- I wore just a headband to cover my ears under a helmet. This worked.
- The only tricky part was my hands. I have not yet got the hardshell or under-40 temp. gloves, so I wore my 40-60 range gloves over a fleece set that I bought just yesterday. Curiously to me, my fingertip starter to feel really cold about midway through my 30-minute ride to work, but then warmed up in about the last 5 minutes where they did not feel cold upon arriving. When I ask about a critical difference between the temperatures of 15 and 25, I am wondering how badly my fingers might hurt, even if they could go numb.

The ride is 8 1/2 miles and this morning I averaged my usual speed of 17-18 miles per hour. I reckon that a fast(er) speed will help with body warmth or cold-feeling, as well as a relatively short distance. (I commute the same on every dry day, but haven't ridden yet when the temperature fell below 24.) I have also noticed that when I do this morning ride to work after drinking hot coffee, 25 seems to feel about the same as 35 after work, when I haven't had coffee or other hot intake for several hours.

Thoughts, anecdotes, warnings? I already know it probably looks foolish riding in bike shorts under 40 degrees, let alone 20. Could something bad happen with my breathing, perhaps?

You wore more than me (upper body) on my single digit morning commute today. I do, however, wear compression pants over chamois, and a pair of breathable pants to block the wind. I personally wear goggles and a balaclava if it gets below 20 degrees or so, as the wind on the eyes (I wear contacts) causes my eyes to water excessively. I also like mittens instead of gloves in sub freezing temps. And I wear boots over wool socks, and ride platform pedals.
One thing I will say, is that when the temp gets down near 0, any kind of headwind will penetrate and cool unprotected appendages, including the one between your legs. I carry an stocking cap to stuff down there if needed...no fun arriving to your destination in good order, but with a frozen banana.

I take it that I should be fine then, what with my upper-body warmth emphasis. (No worry about the banana!) I wonder though, if wearing mittens would make it harder to shift the gears? Also I have just clipped (?) pedals right now, so have not considered boots or warmer shoes than just double or triple socks. Thank you for your feedback!

I suppose almost anything could work for a half hour ride but uncovered knees at that temp is flirting with the potential for serious tendon and ligament trouble. This assumes you are working your knees reasonably hard and not just coasting along. In my view shorts in the mid-twenties is borderline insane. Really any uncovered skin at those temps risks frost bite with the typical apparent wind speed we see on bikes. YMMV

25° on down I wear a balaclava every time, or wrap a scarf around. It will warm the air before you breath it.

outer layer is a wind breaker or cycling jacket at 20°, the rest sounds fine but cover the legs. At that temperature I give up on going fast so it doesn't really matter if there's some flapping.

Pedal enough to keep up a sweat and you will be fine. What you are wearing becomes more of an issue when you stop. I x-country skied one day in -35 F (that is minus). All I wore was a sweat shirt and sweat pants with a set of U.S. Military surplus EWCS light weight fleece under suit. No problem at all while heated up and sweating. Potential big problem when stopped for more than a few minutes. Working up a sweat, and more importantly wearing clothing that wicks that sweat away from your body (it freezes when you stop and drives down body temperature quickly) will keep you warm.

I get really concerned over exposed skin in the wind. Wind chill can be downright critical when the nominal temp is 20F and lower. The scariest I have run into was one day last winter. The temp was below zero (had been for days) and the wind chill one day was -35F. What frightened me was that I could not perceive a difference between that an 15F. Obviously -35 is dangerously cold, but I really could not feel it.

Marc

For me, the changes from 15 from 25 degrees F is I consider a face covering around 15 degrees or so (I wear a nomex face mask) and I wear lobster gloves not regular gloves at that temp. When I gets around zero, l go with another "level" of covering (mittens and headwind wind pants over my heaviest tights, and maybe googles over my glasses).

Lobster gloves let you shift, though they are more clumsy. My winter bikes have had old fashioned thumb shifters that let me shift even in heavy mittens.

If you value your knees, you really should be covering your legs. I wear tights or knee coverings any time that temps are below 60 F. I would never consider riding in freezing temps without knee coverings.

That said, I notice a big difference between riding in the mid-20s and mid-teens. For one, my water bottle freezes solid during my one-hour morning commute when temps are in the mid-teens, but they just get a little slushy in the low 20s. My hands and feet are totally warm in the 20s, but they start to get chilled and a little numb in the mid-teens. In the 20s, I can get by with a single long-sleeve base layer under my jacket, but I will add a long-sleeve jersey for temps in the teens.

Even if you don't feel cold, it's probably good to wear long pants just to keep your knees loose and limber. Your risk of injury goes way up when your joints are cold, regardless of whether or not you feel cold.