The Klymit Inertia X Frame is designed with the ultralight backpacker in mind; however, it isn't very versatile and isn't comfortable. Buy it if you want one of the lightest full-sized pads on the market and don't mind a loss in comfort or warmth.
Performance Comparison
While other pads eliminate weight by removing foam or using lightweight materials, the X Frame takes an aggressive weight savings approach by eliminating portions of the pad itself.
Photo: Jeremy Bauman
Comfort
For an inflatable sleeping pad, this one is amazingly uncomfortable. When used side-by-side with other competitors, our testers found this pad just as uncomfortable as foam pads like the Best Buy winning Therm-a-Rest Z Lite SOL and the Therm-a-Rest Ridge Rest SOLite. Unfortunately, the X Frame's unique and aggressive design doesn't lend itself to comfort in the slightest. Unless you lay on this pad perfectly, you will feel the ground. Sleeping on your back seems to be the most comfortable, but we would not recommend this pad if getting a goodnight of sleep is a priority.
The Inertia X Frame comes with a hand pump that allows you to inflate the pad beyond what's possible by mouth. Our testers found this to be unnecessary because an adequate pressure can be achieved without using the pump.
Here you can see how the X Frame is mapped. The mat is most padded around your hips and shoulders along with some small baffles for your feet.
Photo: David Clark.
Weight
Low weight is the biggest reason to purchase this pad. The regular size we tested weighs a scant 9.1 oz before the weight of the included hand pump (we didn't like using the hand pump because blowing it up with our mouths seemed adequate). The small version (Inertia X-Lite) weighs just 6.1 ounces! While it is incredibly light, we think the abysmally low comfort score is too great a price to pay. In our opinion, cutting holes in a pad is a poor way to save weight compared with simply reducing the length and using a pack for your feet. For instance, the size small Therm-a-Rest XLite weighs just 8 ounces, making it lighter than the X Frame, much more comfortable, and warmer. The X Frame is meant for those who need to shave every last ounce off their kit and don't mind sacrificing comfort.
Warmth
With an R-value of 1, this pad is among the least warm in this review along with the Sea to Summit Ultralight. If you're sleeping directly on snow, expect to be really cold.
The hollow portions of the pad allow your sleeping bag to loft into them. The idea is that your sleeping bag will help insulate you from the ground. However, we did not find this pad to be very warm in practice. It is best used in summer.
Photo: David Clark
Packed Size
This pad packs down about as small as a can of soda so you won't notice it in your pack. The next smallest pad was the Sea to Summit Ultralight, which is about twice the size of the X Frame.
The X Frame is ridiculously small. It is half the size of the next smallest pad we reviewed. Buy this product if saving space is a priority.
Photo: Jeremy Bauman
Durability
The top and bottom of this pad are made with 30 and 75 denier polyester respectively. During our testing, we didn't note any issues regarding durability.
Best Applications
Without question, the best use for the X Frame is ultralight thru-hiking. If your goal is to strip every possible ounce off your base weight and reduce the size of your pack, this sleeping pad is worthy of your consideration. However, the vast majority of our testers prefer to spend a few ounces and upgrade to the more comfortable Therm-a-Rest XLite. That said, if you're set on a minimalist hiking style, pick up the X Frame and crank out the miles.
Value
Typically, ultralight backpacking equipment costs a premium but not so with the X Frame. Retailing for just $72, you can lighten your pack without lightening your pocket book. Keep in mind that this is a specialized piece of gear that really only works well for ultralight backpacking and it's not very warm. If you're looking for one pad that'll work for car camping and general backpacking, we'd recommend a more comfortable pad like the Therm-a-Rest X Lite or Sea-To-Summit Ultralight. Alternatively, if the low price tag is appealing to you, consider one of our Best Buy winning pads: the Therm-a-Rest Z Lite SOL or the Therm-a-Rest NeoAir Venture.
Conclusion
The Klymit Inertia X Frame is an ultralight pad for hikers wishing to purge their packs of every possible ounce. The biggest downside to this pad is the lack of comfort and warmth as it is quite thin and has a low R-value. Similarly, it packs down ridiculously small so you won't even notice it in your pack. Though we appreciate that gear companies continue to innovate and make gear lighter, the X Frame does so at the expense of comfort and we think that weight is best saved in other ways--namely by using a two-thirds length pad.
While you can obviously use this pad outside your sleeping bag, you can also put it in your bag. Doing so will keep you perpetually centered on the pad.
Photo: Jeremy Bauman
