I was in need of a new “3 season” bag as the synthetic bag I’ve used since I was 14 just doesn’t cut it anymore. I was looking for a down bag in the 15-20 degree range as that seems to be the best compromise between warmth, packability, and weight for a bag used primarily here in Colorado. Several options exist that fit those general criteria, but I ultimately chose a traditional mummy bag design in the Big Agnes Bellyache Mountain SL 17. Big Agnes is located in Steamboat Springs, CO and is known for several things – namely tents, sleeping pads and bags, but has also recently begun to dabble in the apparel market with a few down jacket offerings.
The Bellyache Mountain fit a pretty good sweet spot in terms of down quality and fill weight – 700 fill, 21 oz fill weight and weights 2.3 lbs (measured) for the regular size. Big Agnes is one of a few manufacturers who offer down that has been chemically treated to repel water, thus maintaining loft and insulating properties when wet, and the Bellyache Mountain sports their DOWNTEK water repellant technology. The bag also has a nice draft collar around the neck as well as a draft tube down the length of the zipper. The draft tube has a strip of thicker nylon sewn into it to help prevent stuck zippers. Speaking of zippers, the bag is available in both right and left hand zipper configurations – which is nice as 2 bags can zip together for those fortunate guys with girlfriends/wives, or if you’re just one of those weird left handed folks.
Of the half dozen nights I’ve spent in the bag so far, I can say it sleeps very well. I was impressed with the overall balance of space achieved throughout the bag. Some bags can feel a little restricting in the knees and feet, but for my build (5’9” – 170 lbs. Ok I confess, I need to lose about 10 lbs) I felt there was good space in the shoulders, hips, knees, and feet. I also noticed on one particularly cold and snowy fall night last year, that there seems to be the right amount of insulation at the foot of the bag to keep the tootsies warm.
Unlike other sleeping bags from Big Agnes, this bag is not part of their “sleep system”, meaning there is not a sleeve built into the bag for a sleeping pad or air mattress. One potential down-side I’ve noticed with this bag is that the fabric is prone to static electricity build-up. And although the bag doesn’t shock you, it does seem to attract hair and small particles of dirt that take a bit to shake or wipe off. Other than that small, perhaps insignificant finding, I would definitely recommend the Bellyache Mountain to anyone looking to upgrade their sleeping bag.