Bag or pants?!

[Dyffers]

TL:DR: will insulated trousers (and the jacket I already use) give me enough of a boost to be comfortable enough in a summer weight sleeping bag at near freezing temps?



Last week I donated my good sleeping bag to my daughter for the two nights on WRT, and toughed it out my my 'race' bag (comfort rating 10°C ).

I'm a big proponent of multiple use items, so the plan for the frosty night was always to wear my gilet and jacket in the bag and see how I got on. Unsurprisingly I wasn't the warmest, but in actual fact my upper body was fine, it was my legs and feet that were cold in just a single layer.

I've been looking this week at getting a second bag with a comfort rating around zero (I'm a cold sleeper) but I doubt the two of us are going to do many sub-zero trips. So might I get away with buying some synthetic insulated pants / trousers like Montane etc for half the price of a reasonable 800g down bag? The thinking being trousers would get some use at other times so not be wasted money.

[Hyppy]

Imma say no, but I feel the cold way more than I used to. I actually picked up some OMM insulated trews early on in the year, the ones with the Full Monty stripper style zip that'll convert into a bag, to wear in my -6º bag to keep my legs warm, having repeatedly been woken due to having cold thighs even a few degrees above freezing.

[fatbikephil]

I used to find that layering up in a lightweight bag ended up stretching the down so you lost insulation. It was a particular problem for my bum as I sleep on my side at my bum always seems to stick out...
It works better with a quilt. I did one night at -6 in my Vesper quilt with my thermal longs on and down jacket and was warm enough.

[yourguitarhero]

I used to find that layering up in a lightweight bag ended up stretching the down so you lost insulation. It was a particular problem for my bum as I sleep on my side at my bum always seems to stick out...
It works better with a quilt. I did one night at -6 in my Vesper quilt with my thermal longs on and down jacket and was warm enough.

I wonder if there is a market for a massive lightweight net ( think a midge net bigger than a sleeping bag) to put extra insulation around your sleeping bag - quily, jackets, twigs etc

[fatbikephil]

No dafter than some of the stuff you see on kickstart I think Ray Mears advocates stuffing heather in your trousers in his survival handbook!
I've tried layering up quilts too but the sum is less than the two halves so to speak as the inner quilt gets squashed.

[Alpinum]

TL:DR: will insulated trousers (and the jacket I already use) give me enough of a boost to be comfortable enough in a summer weight sleeping bag at near freezing temps?[...]

I'm a big proponent of multiple use items, so the plan for the frosty night was always to wear my gilet and jacket in the bag and see how I got on. Unsurprisingly I wasn't the warmest, but in actual fact my upper body was fine, it was my legs and feet that were cold in just a single layer.[...]

It depends, but in general, yes.
Make sure your ankles are covered well too, they are like wrists. A spot to regulate body temps easily, meaning also getting cold feet and lower legs easily when not covered (well).
Get thick socks, or make some from an old fleece jacket.
Mittens work well too, but they don't cover your ankles completely.
You can always stick your feet in your gilet. A cheer for hooded gilets

I've slept out and was seemingly way too cold, having expected -15°C but it was -22°C. Got very cold riding and once I had stopped I was shivering and especially my upper legs were stupidly cold. Once in the bag the only way to not be too cold to sleep was the embryo position, but my hips were sore from the biting cold (630 g down, R3 mat can only do so much). So I straregically stuffed my exped socks down my bibs to the sore spots and off into never-never land I went.

Also a good meal, some chocolate (or Kendal mint cake if inclined) before sleeping will help with warmth during the night. Also the dilatating effect of alcohol

[Hyppy]

… my upper legs were stupidly cold.

This is what gets me, even at temperature way above those you mention. Like the rest of my body can be absolutely fine but bitterly cold thighs will wake me on a chilly night. I've never worked out if it's just a post-exercise thing or perhaps even related to nerve damage. Before getting the aforementioned OMM primaloft trousers I wondered about investing in some down shorts.

[Alpinum]

I wondered about investing in some down shorts.

My girlfriend has/had an issue with cold hips and uses down shorts from Montbell. Or... when within the right temp range, she uses the down/synthetic mix quilt I once made for her, which is filled with down, but also has some synthetic sewn to the outer fabric at the hips and feet