Rab's New Sleeping Bags Preview

The superlightweight Quantum sleeping bags have been lightened and improved for this spring. First, the inner and outer shells of the bags are now different sizes, viz, the inner bag is smaller. This saves some weight but also promotes better lofting so the bags are slightly warmer than before.

In addition to this differential cut, the baffle walls which were previously cut as simple rectangles are now curved to fit the shape of the bag which again saves a little weight by using less fabric and promotes better lofting.

Finally, the baffles are now made using a fine mesh. This has two advantages. First, it's lighter than even Pertex Quantum fabric at 17 grammes per square metre compared to 30 grammes for Quantum, plus as baffles previously didn't use Quantum, but a heavier fabric, the savings are even greater. Overall the weight of the baffle walls is approxiamtely halved.

Next, the mesh tends to trap the tiny hooks and barbs of the down filling meaning its less likely to slide down the walls of the bag and thus should give a more even fill distribution.

Rab's Neil Mcadie tells us that a Quantum 400 is now approximately 70 grammes lighter than before, which is a significant amount for gramme counters. That holds for all the bags in the lightweight Quantum range.

At the other end of the range, Rab's top mountaineering bags, the Summit series has also had a serious makeover for this spring and, in effect, are completely new bags.

Fundamental to the changes are what Rab is calling the Quadrant Baffle System. That means the bag uses four distinct baffled sections to hold the down in place better.

At the side, there are slanted, box-wall baffles, then the top section of the bag uses trapezoidal baffles while after another section of side box-wall construction, the base sectiion uses trapezoidal construction again. Overall, there are roughly twice as many baffles designed to hold down in place and stop it migrating and causing cold spots.

Like the Quantums, the Summits use mesh for the baffle material and differentially cut inner and outer bags. The toe gets a big, slanted, differentially-cut box foot as well that looks quite familiar. And in a neat touch, while the lining material is mostly Pertex Microlite, the inside of the hood uses the same water-resistant Pertex Endurance fabric as the outer bag to minimise any impact from condensed breath when you're sleeping.

Finally, the range which was previously in 600, 800 and 1000 grammes of fill guise now comes in 700, 900 and 1100-gramme versions which means that the top-end bag will cope with proper high altitude climbing like Everest, but still weighs a claimed 2 kg...