I'm just getting into backpacking seriously, and it's time for me to buy my own bag, rather than using a heavy hand-me-down synthetic REI bag from my sister. I want to buy a super lightweight quality bag that will last and is versatile enough to use on all of my trips. I know that I'm going to spend a pretty penny on this, but I'm hoping that it will be an investment that will last me some years. Most of my trips are in the Sierras in the summer and in southern California in the winter. I tend to sleep a bit on the cool side. I'm a bit over 5'6" and 160lbs with broadish shoulders (for a girl).

At first I was very drawn to the MontBell bags for their stretchy comfort. I sleep on my side a lot and tend to thrash about a bit, so I find my sister's bag (59" shoulder, I think) constricting. But after reading some reviews I'm concerned about the stretch system losing warmth when you strech it out. Do any of you have experience with this system?

Another thing that concerns me is that I haven't found a local (San Diego) shop that carries the MontBell bags, so I don't feel like I'm able to make a good comparison. I've gotten in the Hydrogen at a local REI, and loved the feel of the fabric. The fit of the regular was long enough that on my 5'6" frame I was able to sort-of use it as a quilt without stuffing my legs all the way into it.

As far as I can tell, here are some pros & cons:

Marmot bags:
Pros:
1. light
2. 62" shoulder
3. nice feel
4. 850+ down
Cons:
1. half-zip

MontBell bags:
Pros:
1. possible comfort from stretch
2. full zip
Cons:
1. possible coldness from stretch
2. durability of stretch?
3. "only" 725 down

I guess, here are my main questions:

1. Will the half-zip on the Marmot bags be flexible enough to adapt to warmer nights?

2. Is the superstretch system just a gimmick, or does it really work well?

3. Will I be warm enough in the Sierras on frosty September nights at altitude in just the Hydrogen or the #3? If I choose the Helium or the #2, will I sweat like crazy if I use them on a 50 degree spring night in San Diego?


Please help! And thanks in advance :)

Do you have/bring along other insulating clothing? I have a 15deg down bag and it's HOT in the summer, even unzipped much of the length. My new bag will be much lighter and cooler in the summer but able to be comfortable in cooler weather by wearing my clothes/micropuff pullover in colder weather. Then your pullover or other insulating clothes serve dual purpose as rest stop gear and extra sleeping bag warmth! :) Plus you can do a mix of down and synth for extra safety.

The montbell stretch system does not (in my experience) cause any loss of warmth.

The inner baffles hug the liner to your body, reducing the area needing be warmed. This means it costs less calorically to heat, and your calories can be used eslewhere.

If your stretching out the baffles, your putting pressure on the insulation, which can cause cold spots, but it doesnt matter who made your sleeping bag - youll get cold spots if you compress the insulation.

I love my super-stretch... and yes... it really works. The main thing I DON'T like about this bag is the the zipper pull is not a locking zipper... which is pretty lame... but otherwise... I love this bag. I really like the built-in "stuff sack" feature too. You can compress the bag smaller than with no stuff sack... but it's not compressed nearly as much as with a tiny stuff sack.

I have the #3. I sleep really warm! I've used it in mid-May here in Eastern Canada with just a thin synthetic t-shirt on (just to keep the chill off my arms as I often sleep on my front with my arms outside the bag... folded above head) on 5 degree nights and been nice and cozy (5C = 40F). If it got up to 15C at night... I'd have it unzipped!!! I haven't used it on a warm summer night yet.

One way to deal with the zipper issue on the Marmot is to get the Helium EQ version that has the waterproof shell. I have one, and it has a full length zipper. I can assure you it will keep you warm at 15 degrees. A bag that I've been considering is the Marmot Atom--a 40 degree bag that, in long, weighs a bit over a pound. In Texas, I'm thinking that will be more than sufficient most of the time--and when it's not I can add a silk bag liner for another 9 degrees, and then wear long johns if needed. I love the Helium, and enjoy using it when I'm in cold enough weather--which is not very often. Marmot's "larger" cut is very comfortable for me, and I'm 6'2" and 240 lbs.

Edited by bill.egger on 08/09/2006 16:13:22 MDT.

I own a MB UL down No. 3 -- the non-stretch version. MB's specs regarding weight and warmth are pretty accurate.

Marmot makes good quality gear too -- but tend to be "fast and loose" with their specs. Just be careful that their bags aren't both understated in weight and overstated in warmth.

Great, thanks for the help guys.

I actually have a silk travel sheet that I can use as a liner, and I have some fleece and long underwear, so I'm thinking that I might be able to get away with the Hydrogen or the #3. I'm glad to hear that the stretch system of the MB bags works well for those who have it. I'm thinking that the full zip might make these more flexible bags over all, since I can use them as a quilt more easily.

I looked at the Atom a bit too.. If I had the budget, I'd love to have the Atom and the Helium EQ! I'd certainly be covered in all situations there, but that's a bit out of reach for me.

Hrmm... what to do! I think at this point I'm leaning towards the #2, which I can use as a quilt or zipped all up to keep me warm. But.. the Marmot bags seem so nice. I wish the regular Helium had a full zip. Bah.

Thanks again for all your comments. They're great!

A vote for the Marmot Hydrogen. I also was concerned about the zip. The fears were not realised. It is still easy to use as a quilt in a bivy and no problem to get into and out of.

When I have a bag I can move a lot of down from the bottom to the top to have 4 or more inches of lovely 900 loft goose feathers above me – or the other way – and comes in at around 21oz I am a very happy camper. The hood is an absolute effectiveness winner and one of the reasons why I can comfortably sleep at freezing temps... add in a down vest etc and I'm happy well below freezing.

I measured the Hydrogen at 6in (dual layer)loft at the chest and 4in at the knees to average at 5in loft. Tremendous for a 21oz package that also has a very effeciently designed hood where a huge percentage of bodyheat is lost.