I think I know the answer (well the cheapest answer of course!): I'm looking to sleep out more and i'm perversely drawn to winter nights. I 100% need a new mat with a decent R-value and have one in mind. But i'm wondering about sleeping bags. I currently have a 10+ year old (but in excellent condition) Snupak Elite 3 sleeping bag. It's synthetic and doesn't pack small - but not too large. It weighs 1700g in it's stuff sack, and has a -5'C comfort rating, and when i've used it it's been lovely and warm, not really used for long winter nights, but down to low single digits/frosty nights.

I think it's undoubtedly warm enough, but is it beyond the pale heavy for bikepacking? I'd likely put it on a rear rack rather than on the handlebar, mainly because of weight. I've looked at various options, and i'd basically need to spend £150+ for a ballpark comfort level, but about 600-700g saving. So quite a lot for the weight. Would you bother upgrading? Some of the answer will depend on whether I end up staying out more. Just curious what some may consider too heavy for that kind of bag. I'd be using it inside my Terra Nova hooped bivy bag.

Ta

.My summer kit i get weight weeny about my winter kit i get dont suffer or die about it.

Personally., but I only.go local in winter , pack size would be more of an issue than weight .

Edit also possible you will try it once and not bother again so see how you feel.after a few nights out ?

I sleep quite 'cold' and I know I'd freeze in that bag.

For general winter conditions, I tend to look for something with a minimum of 600g of decent down inside. Obviously, I'd go a bit less it was a quilt but likely nothing below 500g. I'd also look for something with proper baffles and not stitch-thru construction.

That's quite an ask for £150 but is possible with careful shopping and should net a weight saving of at least 600g and a massive reduction in bulk.

The weight/bulk difference between down and synthetic really begins to show when you get to lower temps. I've a Rab sleeping bag (can't remember the model and don't think they make it anymore) that's 1700g and is rated at -35C. I have used it bikepacking, well on the Rovaniemi 150 where you have to carry a suitable bag, and it fills a large stuff sack and only just fits into the Wildcat bar harness.

As stated, in winter it's not about being a weight weenie - you need to survive.

Not mentioned so far is layering. I don't use the Rab for UK conditions, it's rarely cold enough, I layer up two summer bags - well a PHD minim 200 and a Cumulus 150 quilt. Rated at 8C and 5C together they are good to -7C (the formula is R1 - (20 - R2) to get a rough starting point), I've used them down to -6C and been fine so the formula is just about right for me. Together the two weigh about 200g more than a single bag rated to that temp, basically it's the weight of the shell material of one of them.

So get a bag/quilt that will go over your current summer bag - needs to be a bit bigger than normal so it doesn't squash the inner bag - much more likely to be within your budget. If you got an "autumn" rated one then you are covering all bases.

That is a very good idea might try it with my 10 degree bag and 5 degree quilt.

Worth noting synthetic always packs bigger than down, that might matter to some .

I love a winter bivvy, but it is rare I actually do it, however there are some groundrules I follow:
The bag is my cumulus quantum 150 - it's rated to -5 but that's a stretch
I wear a base layer and leggings (don't ask for pics)
A light down jacket really boosts the setup

So it's not just a bag question, but a whole sleep system question... (I hate the phrase sleep system, but it does seem to be correct in this case).

So think about how to use the kit you have to sleep warm. Oh, and have a decent feed before bed- that warms from the inside!

Thanks for the thoughts so far, all good points. I think it highlights my lack of decent sleeping bags. My summer one is just a snugpak jungle bag, which isn't warm, and I have nothing between that and the elite 3, I just rely on merino baselayers for extra comfort, even in summer sometimes because the bag is too cool!

I can see the benefits of a decent amount of down giving warmth and reduced weight and pack size. I'd layer up bag types if I had the right selection...think I need to perhaps look at an autumn/3 season bag and a quilt, one or the other or both might cover most bases as suggested. Sounds more expensive than hoped, but I probably need to get it right to enjoy being out. I also seem to be sleeping cooler as I get older, so shouldn't skimp.

I use PHD down socks & down trousers, with an old Karrimor down jacket, inside a sleeping bag in winter. They have the advantage of being wearable whilst I'm shuffling about making breakfast on nippy mornings .

Well, ended up getting a warmer mat and a 3 season down bag for a decent price. Went fairly budget with oex, as I wanted to see and feel stuff before buying it. Oex chimaera ev500 bag, which is 1100g and packs down smaller than my other non down bags. Cost less than £120. Sure it has it's compromises, but it doesn't me for colder nights, and adds more options for me.