[pct-l] Mont-Bell sleeping bag experience?

[Jim Marco]

Peggy,
	I agree with the others. The Montbell super spiral is a good bag regardless of theoretical issues. I find I can toss and turn all night and stay warm in it. 
	One theoretical problem with the Super-Spiral or earlier Super-Stretch bags is that they get thin if you really fill them. A UL SS#1 has about 18 ounces of fill. In one configuration (a 58" girth) this leaves a 14degree bag. However in a 68" configuration it will leave about a 20F bag. Worse, as was mentioned, it may not expand, evenly. Leaving a few cold spots. An *example* where stretching is bad: adding insulating layers to extend the bag becomes less effective because they expand the bag more. So, while possible to add a down vest or sweater, and two layers of long johns, they expand the bag's diameter more, losing part of the loft(insulation) DUE to the expanding shell. Of course, the bag's down insulation is still supplemented by additional clothing, just not quite as much as a standard bag. Note that I am discounting normal fabric stretch.
	Another theoretical problem is the DWR coating. Due to the stretching, this can open pores in the fabric, especially around the sewn baffles and seams. DWR does not mean water proof, so tossing and turning can exacerbate the condensation/rain or mist problem from the outside environment. This usually does not crop up for several years, but, the Super-Stretch bags tend to lose the effectiveness of DWR a bit quickly. Difficult to replace on a bag, due to heat activation, since heat can damage the shell/zipper. Other non-heat set alternatives are not as effective, but maybe I am being a bit too cautious.
	The next theoretical problem is again due to the stretching. Especially at seams, the fabric will separate slightly leaving an avenue for shedding the down. While this doesn't really effect the bag's performance, finding one or two down plumes in the morning can be a bit disconcerting, "Did the shell tear?" Not so with other bags. Finding 1 or 2 down plumes per week is more normal. I really don't care to hike with feathers in my hair, either. Regardless of how I look, I check the bag for down leaks more often than a normal bag, always a waste of time...well, usually.
	The last theoretical thing about the bags is the extra material needed to accommodate the stretching. If you are not rotund, then this is, fairly, just dead weight. Everything weighs something. So these bags usually weigh a bit more than a Western Mountaineering bag of similar fill, usually by 5-6 ounces. But, WM bags run a bit slim.
	The UL SS bags are really well built. The long has room to pack cloths in the bottom and stretch enough to let you change IN the bag. This can be important if the hiker with a tarp stops at a park and has neighbors. Generally, by keeping the bag close, you notice far less bellows effect when you roll, toss and turn. And, by placing your inflatable pad (NeoAir, Neoair XTherm, Klymit Inertia) INSIDE the bag, you can usually stay a bit warmer than sleeping on a cold pad. You cannot do that with most bags. So there are compensations with the stretch vs the various theoretical problems.  
 	Overall, I like mine (the older UL Super-Stretch Hugger #0.) I would buy one again, if needed. 
   	     My thoughts only . . .
			jdm