The world's most in-depth and scientific reviews of outdoor gear

Klymit Inertia X Frame Review

If packed volume and low weight are all you care about, this is your pad. If you want comfort, versatility, or warmth, look elsewhere.
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Price:  $70 List | $34.73 at REI
Compare prices at 3 resellers
Pros:  Weighs just 9 ounces! Packs down ridiculously small
Cons:  Uncomfortable, not warm, air pump and pump valve add unnecessary weight
Manufacturer:   Klymit
By Jeremy Bauman ⋅ Review Editor  ⋅  Jan 17, 2016
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49
OVERALL
SCORE

RANKED
#27 of 27
  • Comfort - 30% 1
  • Weight and Packed Size - 30% 10
  • Warmth - 20% 1
  • Ease of Inflation - 10% 9
  • Durability - 10% 5

Our Verdict

The Klymit Inertia X Frame is an innovative ultralight air core sleeping pad that uses baffles in key places to keep you off the ground and save weight. The pad is the lightest and most compressible "full length" pad we tested. It weighs a mere 9.1 ounces and can fit in your back pocket when rolled up.

Although the X Frame is impressively lightweight and compact, it has several drawbacks that restrict its use to a specific group of people. 1) The pad's air baffles are "body mapped" to fit someone about 5' 10" in height. Depending on how your body parts match up to it, the pad may not fit you. The pad is also the narrowest of the 20 we tested — it's 18" wide as opposed to the standard 20" width. Thus, wider people may not fit on it. 2) The pad is ideal for people who sleep on their backs and don't thrash about at night. You may not find the Inertia X Frame to be comfortable if you turn over frequently, sleep on your side, or curl excessively. 3) The pad's thin baffles and large open spaces do a poor job at insulating you from the ground below; the pad is best for summer use. In sum, the Inertia X Frame could be a good choice for summer backpacking if you're around 5' 10" and sleep on your back.

Our top rated ultralight pad is the Therm-a-Rest NeoAir XLite, which weighs 12 ounces in the 72" x 20" size. The NeoAir XLite is more comfortable, warmer, and more versatile than the Inertia X Frame. If you're counting ounces, we suggest the NeoAir XLite in size small (47" x 20"), which weighs only eight ounces (put your boots and backpack under your legs).


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Awards  Editors' Choice Award Top Pick Award Top Pick Award  
Price $34.73 at REI
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Pros Weighs just 9 ounces! Packs down ridiculously smallSuper warm, packs down small, comfortable, versatileWarm, comfortable pad, great valueLightweight, warm for the weight, packs small, comfortable, versatileWarm, durable, comfortable
Cons Uncomfortable, not warm, air pump and pump valve add unnecessary weightEdges aren’t as stable as other pads, expensiveToo heavy for ultralight enthusiastsExpensive, edges not as stable as other pad designsHeavier and not as warm as NeoAir Xtherm
Bottom Line If packed volume and low weight are all you care about, this is your pad. If you want comfort, versatility, or warmth, look elsewhere.Our go-to sleeping pad, this model balances the portability, comfort, longevity, and warmth better than the rest.This pad is a versatile, comfortable option at a great priceWeight savings and small packed size do not compromise comfort in this ultralight pad.A great pad for those who prioritize comfort over weight savings, though we still prefer Therm-a-Rest pads without the SV system.
Rating Categories Klymit Inertia X Frame Therm-a-Rest NeoAir Xtherm Co-op Flash All-Season Insul... Therm-a-Rest NeoAir XLite NeoAir All Season SV
Comfort (30%)
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7
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Weight And Packed Size (30%)
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Warmth (20%)
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Ease Of Inflation (10%)
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Specs Klymit Inertia X... Therm-a-Rest... Co-op Flash... Therm-a-Rest... NeoAir All Season SV
Weight 9.1 oz 15 oz 21.6 oz 12 oz 22.8 oz
Thickness 1 in 2.5 in 2 in 2.5 in 2.5 in
Claimed R Value 1 5.7 5.2 3.2 4.9
Length 72 in 72 in 72 in 72 in 72 in
Packed Volume (L) 0.4 L 1.6 L 2.5 L 1.4 L 2.8 L
Width 18 in 20 in 20 in 20 in 20 in
Breaths to Inflate 4-7 27-33 12-14 27-33
Type Air Construction Air Construction/Baffled Insulation Air Construction/Synthetic Insulation Air Construction/Baffled Insulation Air Construction/Baffled Insulation

Our Analysis and Test Results

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.
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.

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.
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.

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.
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.

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.
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.

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.
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.


— Jeremy Bauman