Sleeping Bags: Fill weight, cut, thermal efficiency

I used a swift for a while and really liked it but was looking for a wider bag to layer down clothing so changed it for an Alpinelite.

Any particular info you would like?

Don't the swift and alpinelite have the same (or close to same specs)?

If you miss-typed and meant one of the more narrow FF bags a question I have for you is: for you, was the temp rating true & were you able to push lower than the temp rating and still be relatively comfy?

Well, I think either temperature rating would work (depending on how cold of a sleeper you are). The question you need to answer is how often are you going to need/want the extra 10°F temperature rating? I would get the option that meets your needs most of the time. You can get them overstuffed to give you a little buffer room.

Also, have you considered a quilt? Some people may think quilts don't work for tossers and turners. For some they do not, but myself and others have been happily surprised at how well they work. A quilt moves with you IMO much more naturally than a bag. With a quilt you might lose a little heat when you toss and turn (which is why I think quilts tend to have more insulation for the equivalent temp rating), but with a bag you get knotted up and constricted. Also, quilts let you regulate temperatures much more easily in warm weather.

The swift is a 10f bag and not as wide as the Alpinelite which is a 20f bag.

The Alpinelite did feel far roomier than the swift.

I have the Alpinlite, and it is a really nice bag.
I weigh as much as you do, and I'm only 5'11" tall, and I have plenty of room inside the Alpinlite for layering.
You'll need the 6'6" length, obviously.

I find no issues with using the bag in warmer temps, up to 50*F. I just leave it a little open to vent, and it's fine. You can even use it wide open like a quilt if you want.

Nothing wrong with using the Ultralite bag with the narrower cut, either. It all depends on how thick of a layer you want to wear, and have room for lofting inside the bag. The narrower bag is more thermally efficient, and it will feel warmer faster. And it's a couple ounces lighter.

The way I looked at it was that the Alpinlight was still under 2 pounds, and it left me room to wear a coat inside if it really got cold. This is my winter bag, so it has to be able to work if a deep cold spell comes thru, and I need a thick layer inside.

If I thought I'd never need to layer anything inside it, I would have bought the Ultralite. As for the temp rating, WM has accurate ratings, but I find that my personal needs are to have a bag rated for about 10 degrees lower than I mostly expect to see. I like to feel warm, and I want a margin of comfort if it gets colder than expected.

I'm 5' 10" and use a regular length Western Mountaineering Megalite because I have wider shoulders.

To make it good to 20 F. I sent it back to WM and had it overfilled with 1 oz. of 800 cu. in./oz. down. Cost was under $40.

Now it is warmer and still has the shoulder girth I need PLUS it can accomodate me wearing either my Thermolite insulated jacket and pants or my down jacket (see my avatar).

So for max versatility get the wider bag, esp. for your size, and get a Long, natch. This is about a good night's sleep, not 4 or 5 extra ounces.

** I've unzipped my Megalite all the way, hooked the foot over the end of my Thermarest Prolite pad and used it as a quilt on warmer nights. Fantastically comfortable that way.

Hi Eric,

I rang WM recently about overfill for my Alpinelite and they said 1oz adds 5f, did they tell you it adds 10f?

Hey Everyone – thanks for the replies and things to consider. Hopefully I'll have the opportunity to test a few bags out for fit. Right now I'm leaning towards the standard cut FF bag (in long, of course).

The advice to purchase based on "most frequently expected temps" was a good thing to consider!