Hello there:
I will be walking on the AT in June for 2 or 3 weeks in the northern 1/2 of VA. I am buying a Montbell superstretch. Do I need the #4(37.4 degree bag) or the #7(50 degree bag)?

sleeping bag ratings don't really mean a whole lot. If you are going to be bringing sufficient warm clothing and if you sleep warm (need less loft to stay warm), I'd go with the #7. However, If you are always cold and not planning on bringing a warm jacket, go with the #4. You may want to look into another option. I just purchased the Jacks R Better Stealth for doing the AT (GA-TN). I really like its weight (17.8 oz for a long) and it allows you to wear it like a poncho. It is very useful, light, and relatively inexpensive for what you are getting.

Your not likely to see temps that the #7 bag and some extra clothing can't handle but the Montbell bags aren't cheap so unless you've got a lot of extra coin laying around, I'd go with the #4. You'll get more versatility out of the bag and its only listed as 5 ounces heavier in the long length. A 50 degree bag is a very specialized piece of equipment with limited application. You can always unzip the #4 to cool off on warmer nights as the SS bags have a full length zip.

Ideally, I'd go with the #3 for a 3 season bag if you're doing most of your hiking in the Mid-Atlantic region. You won't see too many situations this bag won't handle on the AT spring thru fall.

Thanks for the feedback. I do understand all the variables make these sort of decisions personalized, but I appreciate any discussion before I make my decision. It can only help me to hear what more experienced people have to say. Thanks again.

Thanks for the feedback. I know I am not confident enough yet to leave the regular sleeping bag approach to sleep. I do like the idea of dual purpose. Thanks for your idea.

I dont really understand how stretch bags can maintain a temp. rating. If you are really small and hardly stretch it at all, wouldnt it be warmer than if you are larger and fully expand it? It seems like the loft would flatten out as it covers a larger area. So are Montbell's temp estimates for a bag that is fully expanded? I am interested in these bags because it seems like they would be easy to put inside another bag for really cold weather, but I want to hear what happens when they are fully expanded.

I just got a Montbell #3 becuase I wanted a fairly cool temperature rating for a bag. I would not reccomend buying a warm weather Montbell. It's too much money to spend on such little material. I almost went with a #2 but the price gap starts to increase heavily there. I've slept in 32F weather with the #3 and I was comfortable, but I'm also skinny so that stretches the inside more for loft. Most other bags feel like a waste of material to me since I am very thin. The nice thing about the stretch is that no matter how big you are, the bag is against you well so that all the loft is being used rather than just flopping over.

John, I can explain my experiences with three MBs, re: your question:

"If you are really small and hardly stretch it at all, wouldnt it be warmer than if you are larger and fully expand it?
- Yes, but they accomodate a 50th percentile male without much stretch (in my estimation). If you are overweight it might be a problem, but then you probably would not pay a premium for a montbell bag to save a few ounces.

"It seems like the loft would flatten out as it covers a larger area.
- Yes, certainly. Most the stretching and repositioning I do is temporary, or stretches the bag locally, for example where my knee is bent and jutting out. Overall though, the bag stays lofted, only stretching where necessary.

"So are Montbell's temp estimates for a bag that is fully expanded?
- I dont know, but general consensus is the temperature ratings are conservative, and correct for most males. My #7 is all I need down to 40'F with an insulation layer.

"I am interested in these bags because it seems like they would be easy to put inside another bag for really cold weather, but I want to hear what happens when they are fully expanded.
- Or, better yet, put it outside your other bag, since the MB will stretch to accomodate the inner bag. Putting a MB bag inside a non-stretching bag would render the super stretch system ineffective. Two MB bags, one inside the other would maintain the system also.

If you are concered about room or loss of loft, buy the long. I'm about 5 10 and went with the long on two of my three MBs, they stretch to 75" in the shoulders.

Another benefit of the stretching is that the elastic has a tendancy to close the gaps and keep the bag close to your body. So in one way the stretch makes the MontBell bags warmer than normal bags.