We’ve already brought you the scoop on Rab’s new for Spring 2010 clothing, but at the same time, the company has also completely redesigned and improved its range of down sleeping bags with improved construction and down.
Serious Research
Rab’s been making down bags for almost 30 years now so the guys know a thing or two about how to make them work, but a couple of years back, they decided to go back to basics with a research project at Leeds University. The aim of the project was to work out the absolute optimum amount of down to use in any given sleeping bag chamber for the best balance between warmth and weight.
The results of the research mean that Rab now knows exactly how much of any particular fill power down to put inside each baffled compartment of any of their bags, so when bags are being filled, the down is precisely weighed out for each chamber. Not too much, not too little. ‘The golden ratio’, Neil Mcadie of Rab calls it.
Hood has neater internal drawcords for 2010
Other crucial factors are the weight of shell fabric – the lighter the fabrics used, the easier it is for the down to achieve maximum loft and the more insulation it will give – and the construction of the bag.
Differential cut and chamber shapes are both important as is the direction of the baffles, so for example, chest baffles may be vertical to reduce down slippage. Another factor here is that Rab uses mesh side-walls inside the chambers both to save weight and because the mesh grips the down and stops it slipping around inside the bag.
The final ingredient is the down itself. This year’s top-end bags use new 850+ fill power, US-rated down, the best the company has ever used. Neil Mcadie says that 850+ is the maximum possible in their experience. The company has switched to US ratings partly because it’s expanding into the American market.
Rationalised Range Rab’s exiting range had grown organically becoming quite hard to understand in the process, so this year, all that’s been simplified with easy to understand categories and less overlap: top-end, super-warm bags are ‘Expedition’, then there’s ‘Andes’, still very warm, ‘Alpine’, where weight becomes more of a consideration, and ‘Neutrino’ which is all about weight savings.
The bags are colour coded – red is very warm, orange next step down and yellow less warm.
Below that level, the cooking Atlas bags are replaced by ‘Ascent’ and ‘Explorer’ bags, still made to Rab’s high standards, but with less highly specced fabrics and fill and at a more affordable price.
Expedition Bags Do what they say on the can: these are the warmest Rab bags out there, use 850+ eastern European goose down and Pertex Endurance coated and water-resistant fabric. To put things in perspective, the 2105g Expedition 1200 has a comfort rating of -29?C and a limit of comfort of -40C.
Features include longitudinal chest and foot baffles, a generous cut – 80cm across the torso – so you can wear down clothing inside the bag for extra insulation, anti-snag webbing tape and lots more. The bags are hand filled at Rab’s HQ in Derbyshire. Sizes: 800, 1000 and 1200.
Andes Bags The Andes series bags are similar to the Expedition ones in fabric, cut and features, but use 800+ fill power down instead. There’s some crossover, the Andes 1000 is a little warmer than the Expedition 800, but mostly they’re slightly lower specced bags, though still very warm.
Baffles are horizontal on chest and foot and cut is 5cm closer to save weight. The 200 weighs just 745g, comfort limit 0?C and even the 600 tips the scales at 1185 grammes for its comfort limit of -14C. Aimed at lightweight mountaineering use.
Neutrino Bags Neutrino has always been Rab’s lightweight flagship range and it carries on this year in 200, 400 and 600 sizes. Inner and outer fabrics are Pertex Quantum, their current lightest fabric for weight saving and better loft. Down is 800 again and there are women-specific versions of both 400 and 600 bags.
You’re not losing that much in performance terms either. An Ascent 900 weighs 1795g and has a comfort rating of -11C while a far more expensive Expedition 800 weighs 1640g and is comfort rated at -15C.
Finally there’s an Explorer range of adaptable travel-esque bags, squarer shape and all round zip and the minimalist Rab Top Bag lives on in two different forms, more about that shortly.
In the shops about now, full details of the entire range at www.rab.uk.com.