Gear Review

Big Agnes Two Track Pad

air + foam insulation
highest available R-factor
extra weight & bulk
winter camping pick

In its two-inch version, the Big Agnes Two Track self-inflating sleeping pad offers a very warm advertised r-value of 6.5.

To put that in perspective, Thermarest's equivalent winter pad, the ProLite 4, is rated nearly 50% less, with an r-value of 3.2.

Exactly how objective those numbers are (and thus how valid the comparison) is open to debate, but it seems clear that the Big Agnes Two Track offers the highest practical insulating value for winter mountaineers seeking a one-pad solution to sleeping on snow.

Two Track on Snow

The Two Track is available in two shapes and two thicknesses: rectangular versus mummy cut, and 1.5 versus 2 inches.

The mummy cut saves weight by trimming away extra material, though of course you won't able to roll around as much in your sleep.

The 2" Two Track is rated to -25°F, while the 1.5" (with an r-value of 4.5) is called a 0° pad.

As you'd expect, the 1.5" pad is about six ounces lighter than the thicker two inch version. All versions of the Two Track come in two lengths: 72" (regular) and 78" (long). These many permutations give you the ability to choose the shape, length, and thickness that will best suit your needs.

Most winter mountaineers will probably choose the mummy cut, because it's lighter and less bulky when rolled. As for thickness, the 1.5" looks like the more tempting option, as it saves six ounces (30 ounces total in the regular length) but still easily bests the insulating value of a Thermarest Prolite 4 pad.

The Two Track's impressive insulating effectiveness comes first of all from the pad's thickness, and second by the addition of a high-density foam core. The foam core in particular gives the pad a welcome boost in warmth versus other inflatable pads.

The promise of these high r-values is the ability to sleep directly on snow without necessarily adding a closed-cell foam pad underneath. Note that there are advantages and disadvantages to both approaches. If you do bring a separate foam pad, you can trim it down so that it just barely covers your body core. A thin strip of foam like this will add hardly any extra weight to your load, and will also prove handy around camp whenever you need to sit on snow (while cooking dinner, for example).

On the other hand, bringing along any extra gear adds bulk to your load, and requires you to keep track of one more thing. The simplicity of just bringing one pad can be highly appealing.

I find that the 2" Two Track does add quite a bit of insulating value over a Thermarest Prolite 4. In my experience, the Prolite 4 is just barely adequate for sleep-on-snow comfort. The Two Track, on the other hand, will indeed let you leave your extra foam pad at home.

Compared to the Prolite, the Two Track makes for a softer bed—the pad is not as stiff, which is either good or bad depending on your mattress preferences. I prefer the textured upper surface of the Prolite, which helps keep you from slipping off. But really, the critical factor in choosing the Two Track versus the Prolite lies in deciding whether or not you need that extra insulation.

The Two Track's weight premium over the Prolite 4 is considerable, especially in the 2" version. If those extra ounces don't bother you, by all means go for the Two Track in cold weather. On the other hand, fast-and-light mountaineers will probably prefer the Thermarest Prolite series, supplementing these thinner pads with extra foam where conditions and safety demand it.

*note: inflatable pads lose essentially all their insulating value when punctured. For this reason, winter campers should always bring a puncture kit along. The Big Agnes Two Track ships with its own stuff sack and puncture kit; these are included in the published weights. Big Agnes Mummy Pads are specially compatible with certain models of Big Agnes sleeping bags—they fit a sewn sleeve inside the bag.

» Bottom Line: A one-pad solution for snow campers.

» Camping Gear Review Index