Rab Mythic 200/400/600 review




Rab’s Mythic range sets a new standard for sleeping bag weight/warmth performance, and are realistically priced too

Pros and Cons

  • Very warm for their weight
  • Care must be taken for longevity

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We test out the new range of Rab Mythic sleeping bags, which offer superb warmth-to-weight performance

There’s something about a super lofty, lightweight down sleeping bag (or jacket for that matter) that gets us outdoorists drooling, and that’s exactly what we were doing when we first caught sight of the new Mythic range of sleeping bags from Rab at the OutDoor trade show in Germany last July. The range consists of three models – the Mythic 200, 400 and 600 – and visually, they are virtually identical, with a shiny, wafer-thin blue outer fabric and plumped-up V-shaped baffles containing high quality European goose down. The specs tell the bigger story, and the headline figures are that the Mythic 200 gives a Comfort Limit rating of 1 degrees C for its 475g weight, the 400 gives a Comfort Limit of -6 degrees C (Rab limit -7 degrees C) for its 660g weight, and the 600 gives a Comfort Limit of -12 degrees C (Rab Limit -16 degrees C) for its 885g total weight. These are incredibly impressive figures, but how exactly have Rab achieved this kind of performance, and what compromises – if any – have been made?

Pertex Quantum fabric is used for inners and outers


Rab have been making down sleeping bags for four decades now – and in fact, this was the first product that Rab Carrington made all those years ago, during his expeditions in South America – so you’d expect them to know a thing or two about it. Interestingly, Rab’s down sleeping bags are still hand-filled at their Derbyshire factory, and what this means is that when they reach their customers they are still in ‘factory fresh’ condition, never having been compressed or stored in any way that could be harmful to the insulation inside.

The basic formula for making down sleeping bags with a high warmth-to-weight ratio is simple: use as high a quality of down as you can, and construct the bag in a way that allows the down to perform at its optimum. This Rab have done by selecting 900 fillpower European goose down, and creating box wall baffles in which to put it in – with a quirk being that these baffles are chevron-shaped, which Rab say concentrates the down in the middle part of the body and therefore keeps you warmer. There is one further key factor that affects the weight/warmth performance of a sleeping bag, and that’s the type of materials used for the inner and outer of
the bag. Rab have opted for a super-lightweight 7-denier fabric, Pertex Quantum, for the Mythic bags, a fabric designed to trap still air and improve the efficiency of the insulation inside. Quantum is constructed from very fine yarns that are tightly woven to give a light and soft fabric that allows the insulation to fully loft, and it is also treated with a DWR to shed water. Speaking of water, the Nikwax-treated hydrophobic down inside the Mythics helps the bags keep performing in damp conditions, and also enables the down to dry out quicker if it does get wet.

Mythics have pullcords for both the neck baffle and the hood

The Mythic bags focus on the fundamentals and don’t include lots of features that may be useful but inevitably add weight, but the designers do seem to have paid particular attention to two important areas – the main zip and the hood. All three models feature two-way zips, enabling you to ventilate if required, or unzip enough to get your arm out. The 200 has a ¼ length zip, the 400 a half-length zip and the 600 a three quarter length zip, with all of them offering a reinforced ‘V’ section of fabric at the zip bottom, a good move bearing in mind how thin this material is and how it might wear at this particular point. All three bags also have a see-in-the-dark zip pull which is definitely a useful addition.

Hoods have always been a strong point of Rab sleeping bags in our experience, and those found on the Mythics are no different. This is an area that could easily be skimped on in the quest to save grams, but not a bit of it. There’s two adjustors for sealing out drafts and getting just the right fit around the face and head. One adjustor is for the internal neck baffle and one for adjusting the hood around the face, and if you’re like me and enjoy covering up everything apart from your mouth during chilly nights, then you’ll be very happy with this hood arrangement.

Packsizes are impressive – seen here next to a 1L Nalgene bottle

We’ve used all three of the Mythic bags, and they are very similar in features and operation. The internal dimensions are identical – 70cm at the shoulders, 52cm at the hips and 41cm at the feet, and the fit should work well even for those with a larger build. Rab have resisted the temptation to make the fit too snug (which would have helped them save more weight), and although the feet and legs are fairly narrow, the shoulders are certainly generous enough. Of course, too much space will make the bag cooler as there’s more air to warm up, but we think Rab have got it just about right in this respect.

Making use of Nikwax Hydrophobic Down, the Mythics on paper should be great at dealing with condensation drips inside your tent, excessive sweating (potentially a big problem if you get ill on an expedition), or coming into contact with damp spots on the tent floor, but what can you expect from this type of down in terms of drying times? We used our entirely unscientific ‘bath test’ to see how long the bag took to dry out after being completely soaked. After submerging the footbox for 10 minutes in the bath, the down had collapsed and the inside of the bag was wet, as you would expect. We then hung the bag up to dry in a well-ventilated room. After about an hour the footbox was starting to dry with water collecting at the bottom of the bag, while about six hours later the footbox was completely dry and the down was fully lofted again. Obviously if the bag was hung up outside with any kind of breeze, it would dry out a lot quicker, and this is a real benefit on a multi-day trip.

Clearly Rab’s Mythic bags are some of the best performing bags on the market, but who are they aimed at and what activities are they best suited to? Well we think the Mythic 400 will have the broadest appeal, with its temperature ratings making it suitable for all but the coldest winter conditions in the UK, and ideal for many worldwide treks. The Mythic 200, with a Comfort Limit of 1 degrees C and a total weight of just 475g will appeal to lightweight backpackers for summer use, and also adventure racers. The Mythic 600 is perhaps the most niche of the models, offering enough warmth for trekking and mountaineering trips to the Greater Ranges, yet perhaps not tough enough for extended periods of use compared to a bona fide expedition bag. Instead, we think this model will appeal to alpinists bivying in winter in the Alps or further afield, where the low weight will justify carrying the 600.

The one word of warning to anyone thinking of buying one of these bags is that they need to be handled carefully if you would like them to have a long life. That’s not a criticism – just a fact of life that applies to this type of super-lightweight gear. The Mythics need to be stored properly, compressed slowly to prevent down escaping, and the hood toggles and zips used gently. Treat them right, though, and the Mythics should give you long and loyal service.

Verdict: Rab’s Mythic range sets a new standard for sleeping bag weight/warmth performance, and are realistically priced too

PROS: Very warm for their weight, bags pack down very small, competitively priced
CONS: Care must be taken for longevity

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