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-   -   Expanding the temperature range of a sleeping bag (https://www.bikeforums.net/touring/1122358-expanding-temperature-range-sleeping-bag.html)

gauvins 09-19-17 09:00 AM


Originally Posted by Doug64 (Post 19871990)

With the new synthetic insulating material, I retired my down bag.

Interesting. We've settled on down largely because it results in much smaller stuffed volume (smaller than a loaf of bread). Yes it is a little more trouble to wash, I suppose. And not fun if you get rained on (no horror stories yet). But the absolutely decisive advantage is that one front pannier is more than enough to store pad+bag+liner+tent+chair.

wrt compressibility -- I imagine that it might be more effective to wear more clothes (the plan is to wear thermal underwear and primaloft vest) rather than adding layers on top of the bag. But frankly I do not know. So I guess that I have a few cold nights ahead of me, trying different strategies.

I've also read about the importance of eating caloric food, that you burn during your sleep. So maybe drinking a glass of olive oil before going to bag is the way to go :)

Timequake 09-19-17 09:07 AM

I will never understand these people. "How do I stay warm if it gets cold at night?" Seriously? It's a wonder some of these people can even get out of bed in the morning without step by step directions from a random person on the internet.

gauvins 09-19-17 09:09 AM


Originally Posted by bikenh (Post 19872094)
This is definitely not the answer you are looking for, at least if you are like most people on here...but it a rather interesting different way to think about the situation at hand and to have a whole new kind of experience on a bike trip.

Sleep during the day and ride during the night.

Excellent point!

hmmm... my question was in the context of a tour planed for next spring, in Utah. Bryce canyon is expected to have cold nights. It is also a feast for the eyes, so the first instinct is to ride during the day. But starting at 4 in the morning (usually the onset of the coldest period of the day) would be memorable. Actually a very good idea to climb at high altitude during the night.

Thanks for a great suggestion.

reppans 09-19-17 10:00 AM

I've also used a campsite down/primaloft sweater/jacket as a torso quilt, but under my sleeping bag/quilt. I find drawing the sweater/jacket waist cord, and then wrapping that around my shoulders keeps it best position through out the night. I'd go with heavier weight long UW over a silk bag liner (which are single purpose).

I'm a minimalist that camps mostly in warmer weather (sounds like the OP). For the occasional colder trips, I use a Gossamer Gear 3oz $18 1/8" Evazote CC pad under my Neoair Xlite. Didn't want to buy 2 Neoairs, and the Xtherm would be way overkill for most of my warmer weather trips. I recently upgraded to a 1 lb 45F down poncho/quilt for most of my trips and will pair it with (inside) my older 1 lb 45F mummy bag for below freezing temps. Pairing bags carries some weight/bulk penalty, but the poncho functionality of the quilt negates a campsite down/primaloft sweater/jacket.

I saw mention of water filters cracking from ice - it might worth noting that most water filters will be rendered worthless way before that point. If water crystallizes inside most filter elements, it will enlarge the micro holes allowing microorganism to pass well before the exterior plastic housing cracks, and you'd never know it.

Edit: fwiw, a proper down hood with face/neck cover vs 'head gear'/hat makes a big difference - a mummy hood that can cinch down to expose just nose and mouth is best, but even a down hood borrowed/zipped off a winter jacket will beat a warm hat.

Tourist in MSN 09-19-17 10:18 AM

4 Attachment(s)

Originally Posted by gauvins (Post 19872146)
Interesting. We've settled on down largely because it results in much smaller stuffed volume (smaller than a loaf of bread). Yes it is a little more trouble to wash, I suppose. And not fun if you get rained on (no horror stories yet). But the absolutely decisive advantage is that one front pannier is more than enough to store pad+bag+liner+tent+chair.

wrt compressibility -- I imagine that it might be more effective to wear more clothes (the plan is to wear thermal underwear and primaloft vest) rather than adding layers on top of the bag. But frankly I do not know. So I guess that I have a few cold nights ahead of me, trying different strategies.

I've also read about the importance of eating caloric food, that you burn during your sleep. So maybe drinking a glass of olive oil before going to bag is the way to go :)

I mostly agree with you on down. I prefer synthetics for canoe or kayak trips if I will be in a tent close to shore night after night. But otherwise prefer down. My recollection of Bryce area is that you do not have to worry much about excess moisture, so down should work great.

Olive oil, just don't change your diet so much that you get indigestion during the night.

Bryce, make sure you bring enough camera battery and memory card. The white stuff in the photos is snow, I took the photos Apr 9 and 10, 2014. We car camped there, rode the bikes instead of driving for sightseeing on the roads in the park. (We left Moab the day before where we biked the White Rim.) If my memory is correct, it was below freezing when we got up in the morning at Bryce. I think I wore insulated gloves on my bike and stocking cap under the helmet. The campsite next to us had a couple from The Netherlands that had a pair of Santos Travelmasters (one with Rohloff) and a Hillberg tent.

BigAura 09-19-17 10:52 AM


Originally Posted by prathmann (Post 19871112)
But note that vapor barriers should only be used when it's really cold - below the normal comfort range of your bag/pad combination.

That was my point: when you're freezing use it. Personally I'd rather not get to the point where my pores shutdown. I'd say --> not a good plan, for a winter tour.

prathmann 09-19-17 12:26 PM


Originally Posted by BigAura (Post 19872452)
"But note that vapor barriers should only be used when it's really cold - below the normal comfort range of your bag/pad combination."

That was my point: when you're freezing use it. Personally I'd rather not get to the point where my pores shutdown. I'd say --> not a good plan, for a winter tour.

Sure if you always know exactly how cold it's going to get you could carry the weight of a bag/pad combination to handle it. But a vapor barrier liner only weighs a few ounces and can greatly extend the usable temperature range of your bag. Very useful when conditions change from those expected. And I've always slept very comfortably when inside my vapor barrier so I certainly plan to continue to bring it along on all tours & backpacks where it might get cold.

Bacciagalupe 09-19-17 01:52 PM

FWIW, I concur with some of the above posters. Speaking from experience, a 40 degree bag will keep you alive in 37 degree weather. It'll also be miserable.

Use the right tool for the job. I.e. Just get a warmer sleeping bag.

mev 09-19-17 02:23 PM


Originally Posted by gauvins (Post 19870136)
We have 40F rated down bags and are planning a trip where the average expected minimum temperature is 37F. So we are planning on a freezing night or 2. We may be able to find some kind of accommodation if the temperature were to drop way below normal, but would rather be safe (read -- "warm") than sorry.

To touch on a slightly different related topic, one thing I like to do is look up the 10%/25%/50%/75%/90% temperature ranges on a site like weatherspark. This gives me an idea of how likely it is to be >5 degrees or >10 degrees from the historical averages.

Typically when I am touring, I'll bring equipment to cope with the 90th percentile cases. The "historical minimums" are often so much colder that if they occur, I'll do something exceptional different like alter my plans, wait out the worst of a cold snap, stay inside, etc. Otherwise, I'll end up way overpacking to cover a case that should be rare.

fantom1 09-19-17 03:16 PM

Agree with everyone about getting the better pad, and about questioning the reality of the bag ratings. I like Exped pads, but whatever works for you.

Also would add that bread bags (or other plastic bag) on the feet to act like localized vapor barriers go a really long way in maintaining body temps. I found out the hard way after getting caught in a storm at around 9k feet haha.

Rowan 09-20-17 04:59 AM


Originally Posted by Bacciagalupe (Post 19873009)
FWIW, I concur with some of the above posters. Speaking from experience, a 40 degree bag will keep you alive in 37 degree weather. It'll also be miserable.

Use the right tool for the job. I.e. Just get a warmer sleeping bag.

Well, well, well... where did YOU spring back from? Hope things are well for you and you can continue posting your usual thoughtfull posts here.

I've carried two lightweight sleeping bags for a lot of my travels. One is down-filled, the other synthetic. They both pack into a medium sized Sea to Summit dry bag, along with a silk liner and inflatable pillow. The two bags allow me to control the warmth factor -- two for cold nights, the down one only for cool to warm evenings, and the synthetic one for hotter nights.

Having said that, I do have a fully-fledged down bag that I use when I know temps are going to be around zero degree Celsius. I also have a synthetic bag that would suit between 10 and 20 deg C, but it is bulkier than the two-bag set-up.

Acquisition of a down-filled Exped inflatable mat also has been a revelation. The only issue was the noise as I moved on it. I solved that my putting the inflated mat into a silk bag liner. Exped inflatable pillows finish the sleeping equipment.

Since getting the Exped, I have been intending to dispense with bags and go with a down duvet-style cover. But the bags all have plenty of life left in them, so I can adapt them to a similar configuration.

staehpj1 09-20-17 06:00 AM


Originally Posted by gauvins (Post 19870136)
We have 40F rated down bags and are planning a trip where the average expected minimum temperature is 37F. So we are planning on a freezing night or 2. We may be able to find some kind of accommodation if the temperature were to drop way below normal, but would rather be safe (read -- "warm") than sorry.

There are a couple unaddressed variables that make a huge difference.

The first is what rating that is. If it is just the vague general rating that many manufacturers sometimes claim it may mean next to nothing. If it is and EN rating that is more useful, but even then there are different numbers in the EN rating system like "EN Rating: T-LIMIT" or "EN Rating: T-COMFORT".

My favorite bag has a nominal 45F rating and if far warmer than a few 32F bags I have tried. I find it warmer than some 20F bags I have tried.

Second I find that individuals tend to sleep warmer or colder, so even with the EN rating you need to consider the individual. The difference between individuals can be pretty extreme. You can expect bags with similar EN ratings to be similar, but it is hard to predict what rating an individual needs for a given set of conditions.

I apparently must put off heat like a furnace because I have used and been happy with my Mountain Hardwear Phantom 45 in temperatures down into the teens F and often get up comfy and warm after having never need to close up the bag tight, only to find everyone in camp complaining how they froze in their colder rated bags.

As far as things to extend the range... Wearing a layer or layers of clothing works well if it doesn't cause the bag's insulation to compress due to a tighter fit. Just piling clothes on top works well too. Keeping the wind off with a bivy or tent makes a big difference.

One caution... Being very warm early in the night may be counter productive especially if you get damp with sweat. I find it better to adjust as the temperature drops. Start out with the bag just loosely draped over you if it isn't yet cold. Progress to getting in the bag, then zipping the bag partway, then att the way, and finally pull the hood drawstring tight (but only breathe through the small opening, not into the bag). I find that taking in hot water bottles is counterproductive because it creates heat early before it really gets cold and cools off when you need the heat.

The very worst approach is to get all toasty warm early on and then get damp with sweat. If I do that I find that I get cold later. I find it better to sleep slightly cool at first and add warmth as the temperature drops, but never to the point of getting even slightly damp.

One other thing... If I need to urinate I feel much colder. The tendency it to avoid getting out of the bag and into the cold, but I find that I actually feel warmer after getting up to pee. Some folks take a bottle to bed to avoid the need to get up during the night. That has worked well when I have done it, but I have not made a regular habit of it.

The thing is that you need to figure out what works for you. I know that most of my friends say that what I do would not work at all for them. Until you figure that out, remember that you can wear all of your clothing in a pinch.

Oh and one other thing... I find that a pair of warm and DRY socks is a huge help when it is cold, at least for me. Don't use the damp ones you had on all day.

skimaxpower 09-20-17 10:33 AM

Wearing a down jacket or vest inside your sleeping bag helps a ton. More versatile than a warmer bag. If it's 37 at night, you'll want a warm layer for the mornings!

bikenh 09-20-17 11:08 AM

I'm not sure if anyone has mentioned it or not, forget what I saw yesterday when reading the initial page. Are you talking 37 average or 37 as record low for the time in question? 37 average could be crushed while you are there. You could end up being there with record breaking cold snap hitting the area at the same time. Just something to think about as well.

On my original post another thought that you might be able to work into the equation, not sure your full trip plans...haven't ever been out there to know the naturedness of the lay of the land to know if it's one way in/one way out or how the full logistics work out Possible to time your legs of the ride, if it's a round trip ride, so you see it both daytime and night time but still ride around the weather.

Thinking of something along the lines of start out around 8-9PM and ride the night through, would work especially/creepily well if you are going to be there around full moon. When you go to come back through the same area set your campsites so most of the area that you rode the night through you are going through during the overnight going in, your going through during daylight coming back out. You might have to take a longish day off or a short night off to pull it off but it would give the chance to see it under both circumstances. Like I said above if you are planning around the full moon it could make for quite an interesting experience.

Spring does make a 3-4AM start time much easier since the sun is setting around 7PM and you could still end up with 8 hours of sleep by 3-4AM. Your only real change from what you normally do would probably be being more committed to getting to sleep with sunset and not telling campfire stories:)

gauvins 09-20-17 12:53 PM


Originally Posted by bikenh (Post 19875178)
Are you talking 37 average or 37 as record low for the time in question?

Bryce NP web page pegs the average low at 37. I was initially planning to be able to sleep near freezing, and if it looked like the low could be lower, book a room somewhere. [MENTION=108802]mev[/MENTION] suggested weatherspark.com. They list Bryce airport (could be a bit different). Nights in the mid 20s seem to be a definite possibility. Bummer...

So... I'll get an Xtherm and will experiment nights on the porch to get an idea. Let's just say that sleeping in a 40F rated bag (it is a Zpacks -- they are excellent and I have no reason to believe that the rating is overly optimistic) with the night's temperature dipping to the mid 30s is one thing, but I seriously doubt that I'll be able to (figuratively) survive the mid 20s. From the porch, no big deal. From the trail, would take away the fun. Being from Quebec, we have plenty of opportunities to be cold, so I'd rather not spend precious time shivering away from home.

Still plenty of time ahead to eventually order a warmer quilt.

J.Higgins 09-20-17 04:41 PM


Originally Posted by tspoon (Post 19870186)
I've got the Sea to Summit brand thermal liner, which uses a hollow fibre called thermolite. I got the 'extreme' version which claims to extend the temperature rating by 14C, although I think the actual extension was somewhat more modest than claimed, and the liner weighs 400g which is a substantial fraction of the weight of a sleeping bag itself. But it may suit your needs.

Another method may be just to take thermal underwear or your winter riding cycling gear (assuming it's not too bulky) and use that if you find you're getting too cold. You can also use the gear if it's cold in the morning when you start out. Cheaper than buying anything too.

I have the same one, and although I haven't had the chance to use it yet, I'll carry it to the mountain with me this weekend.

Western Flyer 09-21-17 12:47 AM

The short answer is “If you don’t have to wear all your clothes on the coldest night, your sleeping bag is too heavy.”
I tour with a 40F Big Agnes down bag. Like most BA sleeping bag it has no insulation on the bottom side but relies totally on the mattress for warmth and protection from the ground. Layering clothing I’ve managed to sleep more or less comfortably in sub freezing temperatures, 30 to 29 deg F. The layers: 2 pr riding socks + Showers Pass WPB socks, liner shorts plus leg warmers + Zoic MTB convertible pants/short with legs zipped on and cuffs tucked into the SP socks + SP wpb pants with the cuff velcroed snuggly at the ankles, a silk turtleneck + a summer weight ls jersey + a winter weight ls jersey + a lightweight down jacket (really helps) + on the most chilling night I dawn my SP wpb jacket, my hands are gloved with a pair of fleece gloves + SP wpb over gloves, and finally and most importantly my balaclava + my SP wpb rain hood cover my head (The sleeping bag has no hood.). The head situation need some work. I do use a silk liner for comfort and cleanliness. The liner adds 1 or 2 degrees F of warmth at most.

I use a Cascade Design Thermarest Trekker R-3.2. I’ve never felt cold or losing body heat no matter the night temperature or worse moisture in the soil. I previously had the original Thermarest (R-2.6 I think) I can’t says there was a noticeable difference in my comfort between the two. Both are many times warmer than the Big Agnes uninsulated air mattress I first use.

If I planned to spend most night in temperature in the low 30s or colder I’d get a warmer sleeping bag.

staehpj1 09-21-17 06:11 AM


Originally Posted by Doug64 (Post 19871990)
The jackets are filled with the same insulating as the sleeping bag; why would it compress the bag's insulation?

Whether it compresses the insulation or not depends on how much room there is in the bag. With a slim snug cut bag compression of the insulation can be an issue when you put more clothing inside the bag pretty much regardless of the insulation.


Originally Posted by Doug64 (Post 19871990)
the new synthetic insulating material, I retired my down bag.

Synthetics are a lot better than they used to be, but they are still not as warm for a given weight or volume as compared to down. Also down bags have gotten easier to manage with the advent of DWR fabric and waterproof treated down.

Yes synthetics work better if wet, but I don't find it too much trouble to keep my down bag dry. I think the last time I got a sleeping bag wet enough to be a real problem was around 1980 or so when I was younger and more careless. I have been using a bivy for backpacking and touring in recent years and what little moisture condenses in the bivy collects in three places.

1. A few drops or a tiny puddle collects under the sleeping pad which is inside the bivy. It never touches the sleeping bag is easily shaken out in the morning.
2. A few drops condense inside the bivy on top and is again easily shaken out in the morning.
3. A few drops sometimes are on the outside of the lower half of the sleeping bag shell and are easily brushed or shaken off, especially with a bag with a DWR shell.

If anything I find it easier to deal with moisture when I use a tent.

None of those issues have been enough of an issue to be a worry even on multi month tours or multi week backpacking trips. It is a little extra effort, but honestly I'd treat synthetics the same way any way. Given that I can get by with a bag that packs to the size of a grapefruit and weighs 1 pound 1 ounce. My comparable synthetic bag weighs exactly twice as much and is at least 4 times as much packed volume. They are both useful in a similar range of conditions (I have used both into the teens F when supplemented with some clothing and warm socks)

berner 09-21-17 10:57 AM

Like a few others here I use clothing to supplement a bags warmth in marginal temperatures, as extra clothing will be carried anyway. While not traveling ultalight, I do work at reducing weight. Part of my tactics is to get rid of fleece, which while warm, is also bulky and heavier than it needs to be. I've substituted light weight puff jackets such as this one. https://www.montbell.us/products/dis...01300&gen_cd=1 It weighs a mere 8.5 ounces, less than a tee shirt. It is a bit warmer than a similar fleece jacket, is wind proof/resistant, and packs much smaller than fleece.

Leebo 09-21-17 12:37 PM


Originally Posted by M69thunder (Post 19870555)
I've been looking for something that will wick away the moisture and drys fast... everything I've tried so far becomes damp, then 4:00am, I wake up chilled to the bone. I actually seem to do better not wearing anything. Just got a new down quilt, they recommend wearing something, mostly to protect and extend the life of the quilt. I've reviewed some silk long underwear, the reviews make me a little nervous about spending that much money on something that may not holdup. Anyone here have any experience with silk? Good or bad.

Big fan of merino wool base layers. Patagonia and Smartwool work for me.

M69thunder 09-21-17 12:57 PM


Originally Posted by Leebo (Post 19878039)
Big fan of merino wool base layers. Patagonia and Smartwool work for me.

Thanks, I'll check them out.

jkrjhn 09-21-17 06:17 PM


Originally Posted by M69thunder (Post 19878087)
Thanks, I'll check them out.

If you're looking for a good wool base layer you should also check out Minus33. (My personal favorite.)

pdlamb 09-22-17 11:58 AM

This has been hinted, but let me state it plainly:


Change into dry clothes before getting into your bag. Stay dry through the night.


It's amazing how even a little sweat getting into your clothes and bag can sap heat right out of you.


Dry socks and something on your head (beany/watch cap/balaclava) will add warmth, but watch out for getting hot enough to sweat!


Other than that, what does your experience with your bag indicate? Are you a furnace or an iceberg sleeper? I've found that I sleep even hotter than normal after a day riding, but some people go the opposite way.

staehpj1 09-23-17 06:17 AM

I didn't really cover a couple aspects of this issue.
  1. I make it a point to know the expected lows as well as the record lows. Then I plan for survival with some discomfort at the record low and comfort with clothing supplementing the bag on the colder nights at the expected lows.
  2. I typically plan to camp where it will be slightly warmer if I expect it to be colder than I will be comfortable. That means not camping on a summit on the coldest nights. Also in the mountains cold air will pool in basins so camping a little above a lake will be warmer than at the same elevation as the lake. That is typically more likely to be an issue backpacking, but can be applicable touring.

waddo 09-23-17 06:41 AM

Simplest and cheapest and most effective way: buy one of those 10 dollar blue closed cell mat (some have silver on one side) and use it as a carpet for your tent. Then put your regular sleeping mat on top. This will give you amazing insulation in below freezing temperature. Only negative is when rolled up they are still bulky but they are so light its no problem to strap them on top of your rack/panniers etc.


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