bikenh

This is both a general thought based off of what I have been reading and experiencing lately. It's also an answer to a PM I got this morning that I can't reply to yet because my post count isn't high enough. Sorry.

After Sunday's cold feet episode the Pearl Izumi Amfib shoe covers arrived in the mail on Monday afternoon. Too late to do any testing on Monday. After I got done riding on Monday the first thing I wanted to do was check to make sure they was going to fit. I had looked at some other shoe covers at the LBS only to find ones that were to small. I wear a size 13 shoe standardly so as it turns out I need a 2XL shoe cover to fit over the shoes. In a quick test I saw the only problem was going to be the cleats as the shoe covers just didn't want to fit all the way over the cleats like they should.

This morning I took the cleats off and put on the shoe covers before heading out the door to give them their first test ride. Temps were already above freezing so I knew it wouldn't quite compare to Sunday when the temps never made it above freezing all day long. I had two errands I was going to run...could have ran them both as one but I wanted the extra miles. I was also planning for a bit of a joy ride after getting the errands run. I was hoping to get in around 60 miles for the day.

The first errand came and went and the feet after 25 miles of biking felt fine. The right leg was another story since I didn't quite get the cleat mounted back in the same place as where I normally have them mounted. I was experiencing a nice ache to the outside of the right calf. After getting home from the first errand I swiped packs and also readjusted the cleat and didn't have any more trouble with the leg again the remainder of the day. I headed back into town for another 12.4 mile ride and by the time I got home from that errand my left foot was getting noticably cold. The right foot was fine. I dropped the pack off and headed back out the door for what ended up being another 20 miles and by the time I got home the right foot was starting to get cold as well. I checked the thermometer after I walked in the house and it was showing the temp back down at the freezing point.

While on the joy ride I quickly started noticing that it seemed like my left foot was hot in regards to the fact it seemed like the cold foot was coming from sweating and not just from being a cold foot. As I took the shoes and socks off I immediately felt the socks, both the polyester base layer and the wool outer sock. Both were slightly damp. It hit me right away what more than likely was going on as I have worn a wetsuit biking several times in the past month to do a little testing.

Neoprene works great when it is right against the body but it sucks BIG TIME when it is away from the body. I've heard some guys talk about wearing sandals with all kinds of socks on and having neoprene socks/booties on. The problem I think with that concept would be you have to have the neoprene right against the body or your feet can't stay warm unless you are riding in mild weather to begin with.

To better explain what I just said...am I wrong in what I'm about to say below?

Neoprene as the base layer works great. It will keep the feet, head, hands or body warm. It will collect the moisture and trap the moisture in. If you take off the face mask when you go to walk into a convience store to use the bathroom and you come back out and put it on, you will notice it will feel cold at first but after a very short period of time the insulation value of the neoprene warms the neoprene and your face back up. If you try to put anything on over top the neoprene the neoprene will shut out the benefit of anything put on on top of the neoprene. If you have on neoprene socks and put wool socks on top then you lose the benefit of the wool socks. They won't help to keep the feet warm because of the properties of the neoprene keeping the heat trapped inside the neoprene 'shell'. It doesn't pass enough heat out to let the wool socks pass any heat back to the feet.

Now on the opposite side of the equation if you put wool socks on first and then put on the neoprene socks/booties/shoe covers then all you are doing is trapping moisture causing the base layer and any other insulation layer to get wet. Unless it has good wet to warmth characteristics like neoprene itself has then it becomes pretty much useless. It now acts a 'drag' and does nothing but helps to cool the feet down versus helping to keep the feet warm. The main insulation layer...the neoprene isn't getting the full effect of the warmth from the feet because the wool socks are taking away some of the heat. The neoprene now isn't getting as warm as it would if it were right against the body so it isn't acting like the nice reflector you want it to act like. As a result the whole system gets dragged down the tubes. The only way you could even hope to save the system is to keep the feet from sweating.

Everything else I was wearing today was the same as what I had on Sunday when I rode the 102 miles in sub freezing temps. Sunday my socks were dry when I got home, unlike today. Sunday I didn't have the neoprene shoe covers on helping to trap the moisture in the socks.

I saw someone's post last night talking about taking the warm ankle concept to a much greater extreme...going further up the leg. Keep the lower part of the leg warm and the feet will stay warm. I'm tending to think that is more true than anything else I've heard thus far. Not just the ankle but clear on up the calf.

It almost seems more like you have to, all dependent on just how cold out it actually is, keep from the top of the calf down warm and keep very little on the feet if you want to use any neoprene at all, unless the neoprene is sitting right next to the skin. Neoprene really does trap in both the heat and moisture. It's seeming more and more like you want the neoprene right against the body versus away from the body, that means you can't put anything on the feet besides the neoprene though so you have to keep the legs warms up above if you want to keep the feet warm.

Am I incorrect on this? If so what am I incorrect on. The past several days have really started to key in on several different things I have been noticing and this is one of them that really stands out. Maybe this is one thing I might finally be starting to get a decent hold of. It's only taken an entire winter and now the start of a second winter of biking to get this far.

hairytoes

Your logic doesn't work for me - if the wool socks are trapping some of the warmth, then they are containing it closer to the foot. It doesn't need to get out to the neoprene.

I'm one of the people who use sandals with wool socks and neoprene overshoes. Most typical winter conditions are hovering a bit below freezing in the morning, and a bit warmer in the evening. That results in puddles of near-freezing water, and the neoprene starts to fail when it get really wet. In those conditions, I wouldn't want the neoprene next to my skin. I have neoprene gloves and these are hopeless when soaked - windchill+wet neoprene against skin = frozen fingers.
However, it's rare for water to soak through and even when it does, the damp wool socks still seem to keep my feet warm.
We have had two cold winters, where I was regularly cycling in temperatures of -10Celcius. The system still worked for me.

hyhuu

To the OP: You are essentially correct. The neoprene booties block wind, keep some heat in but also moisture. If one is not out riding for hours, the setup probably works fine. Moutain climbers and other winter-outdoor enthusiasts deal with this problem for years now. From what I'm told, your insulation (woolsocks) is supposed to retain its insulation value even when wet but I don't know for sure if that's 100%, especially when they are being compressed inside the shoes. What mountain climbers do is to use a vapor barrier liner sock (or just plain old plastic bags) on the feet before putting on the woolsocks. That will keep the woolsocks and climbing bootliners dry. The theory is that once the skin reach a certain saturation level, it will stop sweating. The downside is your feet will be wet and prob look like dry prune after many hours. However, climbers only use the VB liner when it's down to near zero or below. There are tons of information on the use of vapor barrier liner socks on the internet. I don't know if it's applicable for cycling and I hope you find what works for you.

Warm legs indeed mean warmer feet. As some suggested, you can put a chemical warmer in the socks around the ankle near the major arteries. That should keep the feet warmer.

brawny

Glad to hear this, hairytoes. I'm a sandals/merino wool sock/neoprene over-booty guy too, but this is the first year I'm planning on riding past Christmas. I've had great success other years this way at -10C, but my ride is only about 10 km, or half an hour on bare pavement. I'm more concerned about how well this will work once we get some snow accumulations - any winter riding I've done in past was with no more than a couple inches of snow - and without any salt/slush on the roads.

I think the key thing is to have wool as a base layer, as it's known to provide good insulation even when wet. Whatever goes over the wool needs to act a wind/water break depending on temperature.

I'm thinking about investing in a pair of goretex socks to wear over my wool socks either in addition to, or as a replacement for the neoprene booties. I'm concerned that they won't provide the insulation that the neoprene does, even if they do work as a wind/vapour barrier. I have some regular booties that I wear during warmer seasons - perhaps these would work, as they're not as tight as the neoprene, and might help trap air between layers?

bikenh

hairytoes, etc.

Given the more I'm seeing after another 58 miles today and thinking more about it I think we need a fair discussion here to really show what is worth its weight in anything.

I know their a sticky topic about what you wore today on your rides. Looking at it I see many concepts being used and many tales to be told. Quite a few times you see people say that is they were going to be out any kind of extended time their feet would end up being cold. That leads to the question...

How many miles are you riding normally with the sandals on? You said you have been out in -10C with them and your feet stayed warm, but how long was you out, 5km or 50 miles. I am talking about being out at one time not part of it in the morning for the morning commute and then again in the evening on the way home. That is two completely separate rides. The length of exposure is going to make a big difference. Right now with my setup I'm using I can go out and ride for a full hour plus with temp right around the freezing point before my toes even start to get cold. I can't say for sure but I'm guessing I could have been out an hour back on Sunday morning when the temps were in the teens F and would have had warm feet still after an hour if I would have had the neoprene shoe covers then, like I do now.

Now in this same discussion I think one other thing has to really be shown as well...given what I said and what hyhuu said. What else are you wearing, not just on your feet but from the top of your head down? In the rides you are on how do you come home, nice and dry or are you sweating quite nicely, aka overdressed. I'm starting to think it's not just the lower legs that you need to keep warm but everything from the top of the head down. I haven't tried the idea out yet it came to me today while I was out riding. I noticed the one difference between Sunday, Monday, yesterday and today was the fact I wasn't wearing anything more than a fleece head band for ear warmth the past three days, but on Sunday when I didn't have the neoprene shoe covers I was wearing a neoprene face mask most of the day and the face mask has most of the top of the head covered as well. Their is a small part about half way down the back of the head where it is open to let excess heat escape and its open in the back of the neck as well. I had more heat escaping through the head the past three days and I'm starting to think that was causing the feet to cool down easier. Got some testing out to do once this next storm front gets out of the way that is suppose to bring rain tomorrow.

Yeah, I know, how do you keep everything in moderation so you aren't sweating up a storm but you are keeping everything warm enough at the same time while you are out for the long haul. Quite naturally if you are staying warm for the long haul you can stay warm for the short haul as well. I guess I would rather off be able to stay warm on a 50-100 mile ride that way I know I can stay warm on much shorter rides if I have to using the same clothing.

BY the way hairytoes I have use neoprene gloves in the past and a neoprene balaclava. I've gotten sweaty with the them and haven't had any kind of problems with them still keeping me warm. Sure, if I take them off to go in a store and then come back out and put them on they are cold but they warm right back up. The neo face mask is the same way. The only trouble with the neoprene is once it's wet it makes you start thinking 'clammy' right away...especially around the face. My neo gloves were starting to rip apart and the balaclava was also ripping apart and it didn't cover most of the face like my new face mask. My new one has a cutout for the eyes and another cutout below the nose. Otherwise the whole face is covered with the new mask I'm using now. I just need to find a way to dechemicalize the darn thing so it won't make me itch thanks to using it.

bikenh

I thought you wanted to use a line sock before the wool socks. I have been using a polyester dress sock underneath the wool socks. Your idea of going straight to wool is something I'm going to have to try as well.

I use to be using a very similiar situation to the VB liners. Last winter I was wearing a...mostly cotton, mid calf thermal sock and then putting a shopping bag over top of the sock and then putting on another sock, same kind, on top of that. Yeah, my feet were cold all winter long last year. I'm going to do some playing around with this concept again. I don't think I ever placed the shopping bag right over the bare foot last year at any point in time. I think I always tried to give the moisture something to stick to first.

I'm not so sure one of my biggest problems isn't the fact I have size 13 feet. That doesn't leave me much room to play with. Before I got the shoe covers Monday afternoon I alway had plenty of room for movement in the shoes. Now with the shoe covers on the shoes fit quite snugly. I wandered before I ever left home yesterday morning to go for the first ride with them if that would end up causing me trouble or not. I'm still questioning that. I wasn't expecting the shoe covers to be quite that snug on the shoes to say the least. I must say compared to my old way of handling a little wind protection and some salt/sand protection the shoe covers sure do look a whole lot nicer. LOL

I'm not sure I could do much with chemical warmers. I hear people talk about putting them down the shoes by the toes. How? There isn't enough room for me to do that. With the shoe covers on its even worse. I might be able to stick them down by the ankles...maybe.

electrik

Keep your feet dry. Water conducts heat 20(?) times faster than air and will thrash any gained insulation value from neoprene in the real cold.

Vapour barrier are only good for extended cold weather use - when your insulation layer can become comprised by moisture since it never dries out and moisture freezes in there. This is what bunny boots are for and VB barriers for your sleeping bags. You do not want sandwich bags over your foot.

You want a wool sock next to your foot. Change the sock, just like the GI did, when it gets wet.

bikenh

electrik,

Some hard questions that won't have the easiest of answers when you stop and think about them. I promise. It kinda shows where all the trouble arises when it comes to keeping the feet/hands/body warm for so many people. Like I pointed out to hairytoes, so much depends on how long you are out. It isn't until I've been out an hour that I start to have trouble anymore. Anything less and I don't have cold feet. The length of exposure will start to bring down the system sooner or later. If the system works for the long haul it will work for the short haul as well.

I know one of the crazy things I've been thinking about doing here mid week next week(weather depending) is going for an all-dayer. How many miles can ride sunrise to sunset on the shortest day of the year. Not only am I curious to the see how far I can go with the least daylight but I know it will be a good test of any warmth system. If I don't get cold while being out on the bike for 9 hours than I know I don't have anything to work about when I'm only going to be out for a short 45 minute ride.

That aside, back to the main point-----------------

As I have heard said many times here and on other forums involving winter time outdoor activities the philosophy of staying warm involves 3 layers, a wicking layer, an insulation layer and a wind/water shell.

I may be wrong in this but to do it correctly each layer should be a separate layer and none of it should combined.

Given that, go out and explain your layering scheme.

The wicking layer:

You say the wool sock should be right against your foot. So you are saying the wool sock is the wicking layer...correct?

The insulation layer:

What are you using for your insulation layer? Again, by combining layers you are losing value in the system and will end up cold.

If you are using the wool sock as your insulation layer than what are you using for the wicking layer?

I know I have read of people using polypro/polyester socks as the wicking layer, against the skin, and then putting the wool sock on over top of that. That's what I've been doing. It has helped big time since I started doing this, I will fess. It's only working out to about one hour though. Beyond that the concept is useless and the feet start slowly cooling down the longer I'm outside.

Isn't the polypro/polyester, wool sock combo being used as it is suggested(wicking/insulation)? You say having moisture right next to the feet helps to cool the feet down 20 times faster, why not try to get some of that moisture away from the feet by using a proper wicking layer before you put on the wool sock?

Doesn't using one sock to serve two purposes, even though it does have the capability of doing both defeat the purpose altogether?

Your system could work if you are using two wool socks, one as the wicking layer and one as the insulation layer. Is this what you are suggesting?

----------------------------------
Before I editted my initial post in the thread, prior to ever posting it I think I put in the comment in the opening paragraph that this could lead to some rather interesting discussion. I still think the same thing and this time I will leave the comment in.

hairytoes

To the OP; nearly all my miles are done riding to work. That's 25miles away by the shortest route, and in good conditions I ride it in 1hr20. In good winter conditions 1hr 30. In bad weather in winter . . . . well, it's taken me 2.5hours to get home at times.

I think you are overcomplicating things. The '3 layer' idea doesn't necessarily mean 3 separate garments, it means you need to think of the 3 functions that help keep you alive.

Have a read of this: Buffalo clothing
I use wool hiking socks, the type that have a loop-pile against the skin. The loop construction helps wick moisture away from the skin and passes it out to the knit layer. Same idea as Buffalo clothing. In cold weather, I use two pairs (by cold weather, I mean below -10Celcius).

My sandals+socks+overboot combination doesn't work if I have to walk, because snow always finds its way beneath the overboot and soaks my foot. In temperatures below freezing, that's dangerous.

hyhuu

I did not mean to suggest that you ditch the liners. You'll have to find what works for you. If liner makes the fitting too tight then that would defeat the purpose. If anything liner for me is just another part of layering.

About the chemical warmer, you are right that you can't put it in the shoe but the idea is to warm the blood going to the toe - hence the arteries at the ankle. I haven't tried it for my feet (as I yet to have a need to) but I have done that for my hands when I go climbing in the winter and it works great.

bikenh

hairytoes,

What would you call you riding temp? By this I mean how warm do you feel when your riding? After you get to work/home would you be willing stand outside for 5-10 minutes or do you want to get inside immediately so you don't cool down and start shivering? This question does sound really stupid but what I'm saying are you getting to work sweaty or are you just comfortable when you get work and if you had to stand outside doing nothing for 5-10 minutes you would end up shivering?

I know I'm typically in a scenario where I wouldn't think much about getting/changing a flat tire but anything else I wouldn't like at all. I'm typically riding with very little on anywhere. The feet and hands have the most protection of any part of my body by far. The head, when it's 25 or above I'm only wearing a fleece head band to keep the ears warm with a sweat band underneath it. I let the excess heat escape through the head. Last year I was always wearing a neoprene balaclava and I was always sweating...this year I wisened up and decided to take the balaclava off and I don't sweat now at all unless I'm wearing a pack on my back. Below roughly 25 I put on the neoprene face mask. Upper body I'm wearing a mid weight Duofold thermal shirt with a nylon jacket overtop even when temps are in the teens, like they were on the 102 miler on Sunday. The legs are a pair of 80/20 cotton/polyester long johns with the tights on top...yesterday I did experiment with putting the tights on first then the LJ's with a wind shell on top. Other than the ragg wool mitts and the polyester/wool sock with neoprene shoe covers that's all I've been using. Nothing else. At least not yet this year and I was out with temps in the mid teens F/-10C on Sunday. Yesterday was the first time for shell pants.

What are you using in comparison? Are you keeping the upper body warmer and as a result it is also helping to keep the feet warmer?

Like I said before, reading most of the comments in Today I wore, it seems like most of the guys that talk about having warm feet also say they wouldn't want to be out much more than an hour or their feet would be cold.

It seems like there is a very fine balance...admittedly that each person has to find for him/herself. But the trick is to having some kind of a reference point to work from. If you don't know where your weak link is coming from you can't solve the problem. Not too many people do long winter rides. Most of them I saw over in Today I wore, were only out for 30-40 minutes normally at any one stretch. They are all bad references. You're the best I've seen thus far. Hence why I'm asking. I can put more on on the upper body and work around with some things to give more on the lower body as well. I haven't cause I'm trying to keep the sweat away as I know that's what creates bad situations. I know with the hills around here putting anything on extra will lead to sweating unless its that darn cold out. I'm riding comfortably right now...maybe at times a slight...real slight bit on the cool side and getting home dry. The only time I normally would say slight bit cool is when taking a break and going into a gas station to use the bathroom and come back out and start riding again. The first several minutes I'm chilled nicely but warm right back up and feel fine again unless I hit a stiff wind(rarely around here thanks to the hills) or get myself on a nice, fast descent.

hairytoes

My route too and from work takes me away from populated areas. In the worst of the conditions, I wouldn't want to count on passing traffic to help me if I broke down.

So I dress appropriately. For temperatures of -10C I would wear:
Buff on head
Wool buff on neck, pulled up round face and back of neck.
wool thermal top, long sleeve
thick short sleeve cycling jersey
Thick wind-resistant winter jersey (not 'windproof'; I find those windproof soft-shell jersey's too sweaty)
Bib-3/4 leggings, under 'winter' full-length bib tights ('winter' in quotes because they actually aren't very thick)
Calf-length wool blend hiking socks
Neoprene overboots
Fleece gloves under long waterproof mitts

If I have to stop, say due to a breakdown, or the weather turns nasty, I carry a windproof/water-resistant jacket to put on over the top.

In that gear I'm comfortable to stop for 10-15min at -10Celsius without shivering.

bikenh

The old saying goes, their is always truth in the numbers...sometimes you just have to get to the numbers.

I think what you just said explains an awful lot and it gives me a whole new approach for trying things out. I just have to figure out how I'm to pull it off. Got to keep the body as a whole warmer while at the same avoiding getting to warm. Around where I live that could be a real problem thanks to all the climbing that I can't avoid. Yeah, pace yourself...I hear you saying it.

electrik

Sorry, i'm not reading all that.

Go look up vapour barriers online.

hairytoes

That's very important. I was reading about arctic workers the other day - the writer was saying that new workers tend to go too hard at work, get sweaty - then they are in trouble when they stop. Experience hands pace themselves.
Clothing that passes the sweat through is very very important, IMHO. I've had my outer layers covered in ice (yes, even in England), but been dry and warm on my skin. I'm a big fan of the pertex and pile gear, and this year will try to get my old Montane P&P jacket usable again. Like most serious mountain gear, this has vents so you don't have to take it off to vent excess heat - just open zips. It's similar to the Buffalo stuff.

clasher

BMX pedals and large sorel/kamik type boots have worked in all winter conditions for me. I wear a thin merino-type wool dress sock and the only moisture problems I had were sweaty feet if it were really mild out. In milder climates or those that see a lot of rain I would use rubber galoshes or overshoes on top of hiking boots or whatever. I use galoshes for construction work in the winter and they are incredibly durable and usually pretty cheap.

Homebrew01

Too much to read, but last year I bought Northwave winter shoes. I like them. If it's really cold such as 20f, I wear neoprene booties over the Northwaves just in case. My Northwaves are a bit big which give the toeas a bit of breating room, and option for thicker socks.
Prior to buying them, I wore regular road shoes with neoprene booties. On the coldest days, I added internal layers of lycra shoe covers & plastic bag to help cover the cleat hole.

mechBgon

My feet don't seem to have much heat to retain in the first place. They are, however, brilliant at sweating I've tried a variety of the conventional wisdom:

Space-age aerogel insoles
Winter-specific cycling shoes, worn very loose
Wool socks
Booties
Plastic bags
Chemical warmers

It's just a matter of time before my feet start to get cold. I think the long-term answer may be some shoe heaters like these: https://www.rei.com/product/745511/ho...m4-foot-warmer Unlike chemical warmers, they don't require oxygen or produce water vapor.

If I were doing long training rides through the winters, that would be very easy to justify. For 20 miles or less, I can squeak by with what I have at temps down to probably 15°F.

bikenh

The funnt thing is after you have been out a while and the feet are cold you get to the point that you really don't notice it much anymore. I was out yesterday. Did a straight through ride. The only stop, was to take a leak by the side of the road. Never got off the bike completely the entire 55 miles. I ended up spending just shy of 4 hours outside. My right foot got cold within the first couple of miles. The left foot took over an hour to get cold. Last week it was the exact opposite sceneraio...left foot than right foot. I left home at 18 degrees F and by the time I got home it had dropped down to 14. I will fess I was a bit worried about walking when I got off the bike but it turned out that wasn't going to be any kind of an issue. Everything was dry, at least sockwise, when I undressed. I was surprised at how much sweat their was on the back of the fleece I had on. I didn't realize I was sweating that much all the time through the back. Yesterday was a bit of an eye opener ride.

Andrey

I do long rides all winter long in upstate NY, I use "summer" shoes with wool socks, neoprene overshoe covers and fleece shoe covers on top sometimes with chemical warmers. Does not matter how well I cover my feet and hands, every 2- 2,5 hours(actually last year I pushed it to 3 hours) I have to get inside to warm up for a few minutes.

Also placing the chemical warmer on top of the shoe and then covering it with a booty lets it stay warm longer. Inside the shoe it does not have enough air to work and if it is exposed to too much cold air it does not warm up either.

I invested last year in Gore-Tex socks. Big disappointment ! I think I wore them a few times, couple of times in rain and my feet were soaked both times and cold. I wore them over thick(and thin) wool socks in winter and my toes got frozen faster. Never tried them under the wool sock though. They also smell bad!
I am thinking of getting toe warmers out of Neoprene without holes cut for cleats and using them as toe covers inside the shoe. I am afraid my toes will get wet and eventually cold.

This year I made custom insoles out of this fabric
https://www.joann.com/joann/catalog/p...RODID=prd48127
It is very thin. breathable and seems like a space blanket glued in between the fleece fabric.
Have not tested it long enough to come to any conclusion yet though

Andrey

I usually carry 3-4 pairs of gloves with me. In the temperature above 20 and all the way to 50 deg.F. I like to have 2-3 layers of gloves, very brethable and not sweaty. Wool/thin fleece liner, then Polartec Powerstretch glove/liner(very stretchable) and then Cannondale 3 season thin glove with pull out windproof cover . Bellow 20 only Marmot ski glove works for me, too sweaty though with the temp.above 20 deg.F.

bikenh

So far the ragg wool mitts and been winning the game for me on the hands VERY nicely. I've been out for 4 straight hours in temps as high as 18 and as low as 14. Never was inside at all. The only leak I took I took outside as there was no indoor facilities handy. My hands stayed warm the entire time. Yesterday I rode a 134 mile ride with temps getting close to 50 by mid afternoon. I wore the mitts all day long. I did uncover the fingers during the PM. The mitts weren't sweaty at all when I got home. I love them. If I could only find the same solution for the feet I would drool all over the place. LMAO

rumrunn6

chemical toe warmers between sock liner and sock. on top of toes not under like they recommend.

or the cheaper hand warmers in roomy shoes.

the more expensive warmers work better than the cheap ones

chemical toe warmers can be reused several times if kept in a tight airtight bag when not in use

Stealthammer

I always wear a polypropylene underlayer with wool because although wool will still keep you warm when wet, you are still wet. Polypropylene "wicks" away the moisture and keeps the surface of your skin drier.

gerv 

Another trick is to get off the bike periodically and walk a bit. That usually warms things up.