Mont-Bell Super Stretch bag + parka?

Alec, i have a few MB SS bags, but NOT the #0.

The SS system is a much gentler stretch system than one might think. It's NOT like having a bunch of rubber bands stretched around you contracting tightly, or an Anaconda snake constricting you. It really is quite gentle and well designed. It's main purpose is just pull the inside lining of the bag close enough to the sleeper to eliminate a lot of extra air space which would otherwise need to be heated by one's body.

It's really very gentle and might actually result in LESS loss of loft than trying to wear a high-loft insulating jacket (and pants) inside of a high quality light tight fitting bag like some from other manufacturers.

I wear a BMW Cocoon or MB jackets inside of my MB bags with good results. I've never quantified these results or performed testing to see how much the lower limits can be extended.

like many bags, i think that the -23F range might be pushing it, though high loft jacket, pants, and down booties might help you get closer to that number.

based upon my other bags, a #1 is fine for me with layers (non-hi loft layers that is) into the mid-to-upper teens which is the lowest i've had it. it might go down to about +10F with similar layers and maybe if i added hi-loft layers, i'd be able to go to 0F, but i doubt, in my case, -7.5F.

i'd consider myself a cold sleeper based upon a diagnosed lack of proper thyroid function.

hope this info helps.

Helps VERY much. Thanks pj!

I have a MB SS # 3 rated to 32, survival to 14. The rating is pretty much on target.

I have had it down to 8 degrees (NOT planned) and I wore a High loft vest, fleece shirt, fleece jacket, base layer, 200 weight fleece pants, wool socks, fleece socks, and had a 200 weight fleece blanket that I used some duct tape and safety pins to modify to an overbag/Quilt. I didn't notice any real loss of loft and the fit wasn't tight with all these clothes on (and I have a 50 inch chest and am 58 inches in Girth at the shoulders). In fact … If I roll around too much at night with just a base layer on, I can spin right around inside the bag.

Since then, I now have a Ray Way 40 degree quilt and a homemade Bivy to push my bag down to Zero, along with a micropuff pullover.

When I get around to saving the cash … I'm going to pick up a MB #0 or Exp most likely … I like the bag that much.

PJ is also very right in his assesment … it's a very gentle bag, not constrictive at all. I would also recommend a Bivy, Tent, or cover … it's a bit water resistant, but it's not GoreTex or Pertex

i've used my #3 down to 30deg with clothing layers but no hi-loft layer. though i did have down sleep socks/booties over wool socks and also a clava on. in my case, i' probably get 20-25 with hi-loft jacket and MB Thermawrap pants.

Wow — a brief post from PJ!!! :) – heh heh…

>>"…heh heh…"

your lucky day. quick, go buy a lottery ticket.

Besides my two MB bags (#2 and #3) , I own a variety of sleeping bags including a Blue Kazoo, Feathered Friends, Slumberjack.

I prefer the MB bags. They work well in our Southern California backcountry (Los Padres National Forest) where temperatures can drip to the low twenties in the winter.

On a quick overnight trip this past weekend, I used the MB #2 in 25 degree weather . I wore only Black Diamond Fleece clothing. My shelter was a Golite Poncho/Tar. Since there was rain predicted for the evening, I used an Equinox bivy. No rain manifested but neither did any condensation.

I love the "stretch" feature on these bags, and do not feel any sense of constriction. I can almost bend my knees into a full "butterfly' position with heels touching. The bags work well if you are a "restless" sleeper, and move well if you alternate from your back to side.

I have come to the conclusion that since the super stretch bags create a "condom" feeling around your body, they actually act as a parka, and therefore stay warmer with less unused space to heat.

I have also worn my MB UL down inner jacket in the MB #3 bag and it makes for a great sleeping system.

One more comment, the MB #2 and #3 bags stow nicely in the Gossamer Gear Mariposa and G5 packs.

Good luck on your race. :)

Paul:

I own a MB #3 as well, although it's the non-stretch version. I've had it a number of times down to 30F (its rated "comfy" temperature) and felt warm. However, I haven't had it any lower and I am therefore curious how low it can go. At what temp(s) did you feel you needed to wear your MB UL down inner jacket when using your No. 3? Thanks in advance.

Alec, I own two MBs, the #7 and #3. You CAN wear your insulation layer without loss of loft. The superstrech system is very gentle; just enough compression to keep the down pockets fully lofted at all times, and the inner baffles in contact with your body or outer clothing layer.

This latter effect minimizes the dead air space continously within the entire bag. Other companies use tight mummy shapes to accomplish this same effect (granted at lower weights..). These several effects of the patented stretch system result in a surprisingly warm bag.

Also, the last baffle of the stretch system has a draw cord; close it off, stuff the rest of the bag inside, and it is packed; no weight of a stuff sack. Put the resulting puff ball in the bottom of your sack inside the pack liner and other items will compress it as necessary to maintain a properly shaped, non-droopy pack.

I could go on and on about these bags…

Ok, I'll chime in here. Recent trip to Colorado Lost Creek Wilderness I was super comfortable in my MB#3 at 32 degrees in skivvies and when the temp dipped to 25, I put on a micro puff and tights and was almost too warm. MB#3's temp ratings are on the mark.



Benjamin,

I took a MB #3 on a 10 day Sierra Trip in late July. On several occasions, I slept outside my Rainbow to view the starry heavens. Temperatures dropped to around mid 20's, forcing me to don the MB UL inner jacket.

Of course your mileage may vary…..all these ratings are only relative as to how you sleep…. hot or cold.

Thanks, Mark and Paul.

Yes, I agree that the MB's "comfy rating" is spot on. Looks like "a little something extra" is needed once temps get below 30.

Ben, sorry i wasn't clearer. i've used it down to expected +30F temps w/non-hi-loft layers. i'm assuming that i might be able to get down to +20-25F w/hi-loft layers top and bottom, plus down socks & a 'clava or beanie. i haven't actually had it down to +25F as i switch to the #2 for those few times that i've expected +20-25F nighttime lows. also, since i'm generally solo and up so early, i am on the go and generating body heat by the time dawn comes and the real lowest overnight temps are reached. this last fact helps some in keeping a sleep system lighter (though heavier fr/a headlamp+batts standpoint) than what might be necessary just based on expected nighttime lows. my trips are generally shorter (2-3d w/some rare 5-7d), so loft degradation is not as much of an issue and i can cut it a little closer than most of y'all.

Alec:
I posted a reader review of MB SS #4 bag and address some ofthe questions you have about wearing hi loft clothes inside. Although not rated as low as the SS #0 bag, I believe my comments are appropriate for the entire line of MB SS bags. I also own a #2 and it's temp rating is spot on, construction is similiar and also 1st rate, and it performs exactly as my #4 bag does. I have often gotten another 5 to 10 degrees out each with the addition of either merino wool LJs or silk ones plus my MB down pants and UL down jacket. A great company that makes great and innovative bags.

Thanks for all of the info and reviews. It really does look like a good fit, and the price isn't too bad for a quality down bag.