Let's go to sleeping bags. For backpacking, skipacking and car camping over the years, I typically have had at least three levels of bags in inventory: summer (30 degree rating), three season (0 degree rating) and winter (-30 degree rating). With small volume not being the highest priority for those activities, I invariably chose synthetic fill of one kind or another. It's all worked well enough.
For bikepacking, however, volume of packed equipment is a bigger issue. Even my lightest synthetic bags were too bulky to comfortably carry on a bike. So, I ventured into the world of down sleeping bags.
|Brooks Range Mountaineering Alpini 30 sleeping bag. Off to a great start.
I decided to start with a summer bag, since I intended to bikepack primarily when overnight temperatures were well above freezing. A summer bag also would be lighter, more compressible and less expensive.
Focused on small volume and low weight, I soon dove into down fill power, which is the number of cubic inches of loft produced by one ounce of a given down fill. Higher fill numbers mean greater loft and insulation. So, for the same weight of down fill, a sleeping bag with a higher down fill power provides more insulating loft and generally is warmer than one with a lower down fill power. Similarly, for two bags of the same temperature rating, the one with a higher down fill power requires less down fill, so it is lighter and more compressible.
All that really adds up in performance and price. That is, the weight and volume of a sleeping bag shrinks dramatically as the down fill power goes up. Not surprisingly, the price shoots up, as well.
|The Brooks Range Mountaineering Alpini 30 sleeping bag packs tiny.
Here it's stuffed into a waterproof Sea-To-Summit compression sack next to my helmet.
Eventually, I decided on the Brooks Range Mountaineering Alpini 30 sleeping bag, with 850 fill down. It weighs but 20 ounces, is rated at 30 degrees and compresses to a volume much smaller than my helmet. Barely over a pound, it slides easily into the lower half of one of the Revelate Designs Truss Fork Packs on my Jones Plus LWB. Amazing.
When I first held the Alpini 30, I thought I received the wrong bag. It felt impossibly light for any practical use. So, I immediately laid down and rested the bag over me. Seemingly within seconds, I felt warmer and soon was overheated. Inconceivable! How could a bag so light be so warm?
The 850 fill down is certainly the starting point, but the Alpini 30 also maximizes warmth by borrowing features from colder rated sleeping bags, such as offset baffled fabric, a draft tube along the zipper, a neck collar, and a toggled draw string hood. For its size and weight, this bag is warm.
I've enjoyed the Alpini 30 on every bikepacking trip for four summers now. A few nights in mid-summer I have had to get out of the bag because it was too warm. A few nights that dropped into the 30's I have added a down puffy jacket to get warmer. But mostly I just sleep comfortably. It's a great summer sleeping bag for the Black Hills of South Dakota.
For bikepacking, I really like how it compresses quickly and easily into a compression stuff sack, unlike the wrestling matches with my old synthetic fill bags. Once compressed, it fits easily in the Terrapin seat post bag, the Salty Roll handle bar bag, or the Jones frame bag. However, due to its low weight, I generally pack it into one of the Truss Fork packs, which still leaves room in the upper half of the pack for a rain jacket, gloves, cap and such.
The only negative to the Alpini 30 is the stuff sack that comes with it. So, I replaced it with a Sea-To-Summit waterproof compression sack. Problems solved.
|The Brooks Range Mountaineering Alpini 30 sleeping bag is tucked into the lower half of the Truss Fork Pack
shown in this picture, leaving the upper half for a rain jacket and such.
I bought this sleeping bag in early 2016 and have used it extensively since. If looking for a replacement or a colder rated sleeping bag, I would head straight back to Brooks Range Mountaineering. Unfortunately, they closed for business at the end of 2018 and I can't find a successor. So, although my next sleeping bag for bikepacking apparently will be from a different maker, it will be 850 down fill or higher, with similar features. I believe it's worth it.