EP 213: The Expanse Sleeping Bag: Deep Dive

The Outdoor Vitals Expanse Sleeping Bag is a roomy, hoodless ultralight down sleeping bag built for side sleepers and anyone who moves at night. In this Live Ultralight Podcast episode, Tayson Whittaker and OV lead designer Brigham Crane cover the full design story, a couple years of prototypes and field testing, and every feature of the Expanse.

Expanse Sleeping Bag: https://bit.ly/4iJwgG4

Have questions for us? Send us a voice message on Speakpipe: https://www.speakpipe.com/LiveUltraLight Or write in to [email protected]!

"I just flat out had some of the best nights of sleep I've ever had in the backcountry sleeping in this bag." - Tayson Whittaker

CHAPTERS

0:00 Introducing the Expanse Sleeping Bag

2:16 The late night in the mountains that started the Expanse

7:03 Designing for sleep quality, side sleepers, and less fiddle factor

10:59 What people want from a sleeping bag: foot room and simplicity

13:13 Why the Expanse is hoodless

15:06 Half-length zipper and a roomier cut

17:32 Why 900 fill power Muscovy down

19:27 Extra room means cold spots: the interior cinch cord solution

23:16 Why a smaller space stays warmer: the heater analogy

26:07 Prototype one: what testers found

33:09 Refining the draft collar, zipper, baffles, and elastic cords

36:45 Why the Long size gets a third cinch cord

39:30 Top to bottom walkthrough of the Expanse

41:36 How roomy is it? Mild taper vs mummy and rectangular bags

43:37 Symmetrical design and top quilt mode

45:20 Field testing: warmth, simplicity, and sleep quality

52:30 Cold sleepers, kids, and friends in the Expanse

54:58 The tradeoff: about 5 oz heavier than a top quilt

58:20 Specs, weights, and 2027 temperature ratings

1:01:25 ExpeDRY down and 900 fill power explained

1:05:00 Wrap-up and how to send questions

HOW THE EXPANSE WAS TESTED

Through development, the Expanse was the design team's only sleep system, year round, in every condition. Every temperature rating was slept at and below its rating. In the 15°F model, Brigham only added extra layers once temps dropped to around 9 to 12°F.

EXPANSE SLEEPING BAG SPECS

Available now: 15°F comfort rating (comfortable at the rating, not survivable), Regular 72" (1 lb 13 oz) and Long 77" (2 lb), bag only

Coming in 2027: 30°F (1 lb 7.7 oz, Regular) and 0°F (2 lb 6 oz, Regular)

Insulation: 900 fill power ExpeDRY Muscovy down

Shell and lining: 10D nylon

DWR treated Zipper: half-length YKK No. 5 coil with draft tubes and anti-snag webbing

Inside width: 30" shoulder to hip, 27.5" at the knee, 13.5" minimum footbox

Room: about 50% more at the knee and 40%+ more in the footbox than some of our own mummy bags

Baffles: horizontal and vertical, with added baffles below the knee to keep down in place

Interior elastic cinch cords: 2 in Regular (knee and foot), 3 in Long

Cinchable draft collar, inner snap at the top of the zipper

Dry bag (1.5 oz) and storage bag (4 oz) included

EXPANSE SLEEPING BAG FAQ

Is the Expanse good for side sleepers? Yes. The Expanse Sleeping Bag was designed for side sleepers who roll through the night. The down is distributed symmetrically with no top or bottom side, so the bag stays equally warm wherever it twists or the zipper ends up.

How do the cinch cords inside the Expanse work? Thin elastic cords run around the inside of the lower bag. Cinching them shrinks the space your body has to heat, without squeezing the down from the outside. Most nights you leave them open. They are there for nights colder than expected.

Why is the Expanse hoodless? A beanie, jacket hood, or balaclava does the job with less weight, and lets you choose your head layer trip by trip. The hoodless, symmetrical design also lets you unzip the Expanse and drape it like a quilt on warm nights.

Expanse Sleeping Bag or a top quilt? At 15°F Regular, the Expanse is about 5 oz heavier than the StormLoft Down TopQuilt. Choose the quilt if lowest weight is the priority. Choose the Expanse if you want to crawl in with no pad straps, roll without any possibility of drafts, and have room to move. What is ExpeDRY™ down? ExpeDRY™ is a permanent nano gold treatment on the down that helps moisture evaporate faster, so the down keeps its loft through humid, multi-night trips.

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