Made with 900 fill down: the Rab Mythic Ultra 360 Down Sleeping Bag (18°F).
Rab is known for high quality builds regarding their down products. Hoping to refine a lightweight sleeping system for cold temperatures, THR looks at the Rab Mythic Ultra 360 Down Sleeping Bag (18°F).
Down, lightweight nylon, baffles, usually a zipper… the sleeping bag world is generally pretty simple: how much down and how high of a fill power, how light of a nylon can you use, where you cut corners on things like girth or zipper length all add up to a weight and warmth to be judged upon. Tradition tells us that brands like Western Mountaineering and Feathered Friends are the holy grail, and generally, the “clothing brands” (think The North Face, Rab, Mountain Equipment, etc.) have been held in a lower regard.
Because of the relatively simple formula, sleeping bags haven’t always felt like an interesting subject to write about, but rather more of a commodity item. A few years ago, my interests were piqued by some innovative designs such as the Feathered Friends Vireo that utilizes a warmer lower half and hoodless design meant to be paired with a down parka, as well as The North Face Advanced Mountain Kit 10 Degree bag, which used both high end ‘normal’ materials as well as a metallic inner coating to add warmth. As experienced by THR contributors Adam Fabrikant and Billy Haas in the Andes and Karakoram this year, the AMK bag boasts pretty mind-blowing warmth to weight, at least partially attributed to its reflective inner coating.
The rave reviews of the AMK bag sent me into a deep rabbit hole, both hunting for an AMK bag of my own, as well as researching alternatives to share with our readers. Out of this rabbit hole came a few cool options, the first of which is the Rab Mythic Ultra 360 we have here.
All the deets and made in the U.K.
I am excited to dive into the nuances of this high tech Rab bag compared to the less flashy, but impeccably constructed Western Mountaineering Versalite. I’m curious to see if the old guard of Western Mountaineering and Feathered Friends is still the best thing available or if folks searching for the best should be considering some of these innovative new bags from some of the bigger companies.
My first impression of the Rab bag is that it is of the highest quality, which one should expect given the reputation of their down jackets. The specs, including down fill weight and temperature ratings, are clearly displayed on their site (360g of 900 fill down), the stitching and construction are top-notch, and the differential cut is comfortable and roomier than expected, which is key for my intended use of colder-than-rated conditions with warm clothes on inside the bag.
I’ll need some cold weather and lightweight trips before writing the final review, but in the meantime, some detailed photos…
Compressed, the sleeping bag takes up modest volume.
The bag liner features TILT (Thermo Ionic Lining Technology)—made from coated yarn rather than space blanket material. And yes, the draft tubes are ample.
A close up of Rab’s TILT (Thermo Ionic Lining Technology)—made from coated yarn.
Basic Stats
Weight Reg Unconfirmed: 645g/22.7oz. XL: 706g/24.9oz
Insulation: 900FP European Goose Down with Nikwax Fluorocarbon-Free Hydrophobic Finish (360g/12.07oz)
Main Fabric: 10D Recycled Atmos™ (27gsm) with Fluorocarbon-Free DWR
Fabric Lining: 10D Recycled Atmos™ (28gsm) with Thermo Ionic Lining Technology (TILT)
EN (13537:2012) Temperature Rating: ISO EN: Comfort; -2°C ( 28°F), Limit; -8°C ( 18°F), Extreme; -27°C ( -17°F)
Rab sleep limit18°F / -8°C
Dinensions Unconfirmed: Packed size14.2in x 7.1in (36cm x 18cm)
Price: $750.00
I’ve been considering getting a Rab jacket with a TILT lining, does that interfere with a beacon? It’s a down jacket so maybe not that big of a deal, but I’m still curious.
This is an excellent question – I worry that it may… As I recall, “anything metallic” or reflective will cause interference. To what degree, I don’t know. I’ll do a little fiddling with this to see if I can get a better answer.
We just got in a Mythic Ultra (I think) jacket, sans TILT lining, it looks awesome.
Thanks, Gavin! Appreciate it. Can’t wait to hear about the jacket as well.
Hey Travis, our article on the UIAA and EMI was on my mind (CAIC used the link in their newsletter yesterday). The UIAA states, “Passive Interference affecting SEND and SEARCH:Metal parts, electronic devices with metal cases, foils and wire mesh, magnets ➔ Keep >20cm distance from metal parts and magnets.” Adding some more. To be clear this is NOT intended to disregard any professional recommendations, it is only to further discuss the original question. Here is how Rob C. replied to a question about interference and the TILT liner. You can find it in part 2 of his PIEPS Pro ISP review. Original question:”Rob have you done any testing to see if the foil on those Rab mythic series jackets interferes with this or other beacons?” Rob’s answer:”i DID test the Rab Ultra Mythic jackets with this thing! I wrapped both the Pro IPS in a Mythic and the Barryvox — didn’t seem to affect it at all. My hunch is the filament/treatment is so fine that it doesn’t impact the sending signal — somebody smarter could probably confirm/debunk that!”
Thanks, Jason. Possible for you to recreate the test? Side note, I miss Rob. 🙁 Thankful I got to ski with him last year.
I love these bags. I have the mythic 200 and 400 (both without the TILT lining) and they definitely outperform their rating. Super well-made. I’ve used the 200 down to -5 celsius with base layers and a thin mid layer on the top. The 400 can easily go to -10 if I wear my puffy layers. After trying quilts, I’ve found the best lightweight bivvy option for me is a thin sleeping bag and wearing insulating layers. Last year I tried a Feathered Friends 40 degree quilt in a bivvy bag and was super cold at -5 even with all my clothes on. Fully enclosed wins I think.
The TILT lining, like the Mythic jacket, requires a leap of faith given the price.