Klymit Inertia X Frame


Fall 2011 pad pad with accessories
Weight 9.1 oz / 258 g 10.3 oz / 292 g
Length 72 in / 183 cm
Width 18 in / 45.7 cm
Height 1.5 in / 3.81 cm



Purchased the X-frame in March of this year and received…

Rating: rated 4.5 of 5 stars
Price Paid: $99.50

Purchased the X-frame in March of this year and received it at work.  The pad weighed in on the postal scale at just over 9 ozs.  

I had to work really late one night and slept on the concrete floor with just a sheet comfortably.  It came with a pump to firm the mattress, but I did not need it. Four breaths and it was fully inflated.

I just returned from a 9-day pack trip to the Bristol Head area of southern Colorado.  The X-frame preformed well on the rocky ground.  I tend to be rough on equipment, but the pad showed no visible signs of wear, so I did not try the patch kit that came with the pad.  It cleaned up easily with soap and water when our trip was over.

I have minimalist tendencies, so I was quite pleased when the pop can sized pad disappeared into the sleeping bag compartment with my 2.2 lb sleeping bag.  I am 6'3" and weigh about 200 lbs.  I sleep mainly on my side, and found the x-frame to be quite comfortable.  Even when the ground was inclined, I did not slide off the pad like my 3/4 Therm-a-Rest.  I had my doubts about the comfort of the cutouts in the pad, but after the 1st night, I didn't think about it anymore.  

Several in our group will probably purchase one before our next outing, they were impressed with the speed to inflate or deflate the pad, the lite weight, and the little space the pad consumed.  I have been a hiker for a little over 40 years now and really appreciate a little more comfort between me and the ground.  

The temps only got down to 30 one night, so I could not make a judgement about the cutouts adding to any extra thermo abilities.  The price was more than I wanted to pay for a sleeping pad, but the benefits of space and weight eased the pain considerably.  

I really like this pad.


Guyz, any chance you could add a few photos of the pad with a tape next to them? I am really curious about the dimensions of this pad.

3 years ago

IF this pad fits YOUR body, it offers impressive comfort…

Rating: rated 4.5 of 5 stars
Source: bought it new
Price Paid: $50


IF this pad fits YOUR body, it offers impressive comfort per ounce of weight. Surprisingly adjustable with its high psi capacity, the sparse structure rewards both the back and side sleeper with a good night's rest. The Loft-Pocket design works best your bag has high-loft insulation such as down or PrimaLoft. It is an unbeatable U.L. combination in cold weather when paired with a thin, closed-cell foam mattress.


  • Highly adjustable for the balance between cushioning and support
  • Incredibly light and compactable, yet highly durable
  • Very comfortable for its size and weight
  • Effectively warm when mated to the right bag
  • Option for Argon inflation creates an U.L. 4-season solution


  • Difficult to completely deflate prior to rolling up
  • Loses width when fully inflated
  • Not as flexible for various body types as solid pads

I was intrigued by this pad, especially considering its radical departure from traditional pad design. I have ultra light closed cell foam pads for keeping pack weight down, but my sleep suffers when I use them, and they're bulky. I was in the market for a light but comfortable addition to my sleeping options. As a happy Therm-a-Rest owner (Basecamp Reg. for years) my first inclination was towards their offerings. I came across this pad on Trailspace, and decided to research further. After research and a chance sale, I made the purchase but was prepared to return it if needed — still skeptical. The logic behind the design was sound, but the execution of the concept? I am pleased to say yes after putting this through its paces in all but the dead of winter in the last 10 months.


This best fits a person in the height range of 5'9" to 6'1". I had my son (5'3") try it and his head was in one of the loft pockets. I'm just beyond this range at 6'2", but it still works well for me. They should make a women's version of this pad, for 5' to 5'5". I would probably benefit well from the XL version. That being said, the standard pad is supremely comfortable for me on my back. I have slept on my side as well, and once I finally found the right way to position myself, enjoyed several nights of restful sleep. The skeletal design only allowed me a couple of optional side-sleeping postures. Not a problem for me, but might be for someone else.

Here is the key to side-sleeping on this pad if you decide to sleep with it inside your bag: set your bag up on its side to begin with, zipper up, with the pad on the side of the bag. Crawl in, zip up, and side-sleep to your heart's content. Staying on this pad when it is outside of the bag was less difficult than I had though it would be. One could easily secure it to the outside of a bag with the right kind of strapping.

The X Frame pad is laughably easy to inflate. It takes me 3 breaths to inflate at the most. The pump really gives me the ability to firm this up, great for keeping me off the ground and debri. However, the more you pressurize the pad, the more it shrinks in width. When firm, this pad shrinks to about 17-18" in width. Length shortens only a 1/2" of so. 

I measured the pad at 9.2 oz, slightly heavier than the claimed 9.1. Total packed weight with patch kit, pad, pump,and stuff sack is 11.2 ounces. This pad will disappear in your pack. It is so small. I can fit the pad, pump, and patch kit in a sandwich sized ziplock. I will say that deflating the pad entirely requires some learning, but most won't feel compelled to completely deflate it because it's so compact to begin with. If you must (and I must), you first open the valve and smooth the air out, then pick it up and wring it out from top to bottom, pulling it through a tight hole made between your thumb and index finger. That usually takes care of it.

Here is a picture of all items, and the rolled up pad after I had inflated it:


I ruined the stuff sack (see the holes?) through my own errors in judgement, but it is plenty big for this kit, which is sooooo small.


The loft pockets work well for my down and Primaloft bags, where the lofty insulation is housed in a thin but strong, flexible fabric shell facilitating loft and expansion. My extra bag, filled with Thermolite (HollowFill 2) and a heavier denier shell didn't fill the "loft pockets" as well. I think the pad works better inside a bag, where gravity can assist in lofting the pockets, if you will.

I used this pad only while backpacking for three days and sleeping at 10k plus, with temps in the mid-upper 30's at night. It kept me warm enough, using my 40-degree down bag and merino lightweight thermals. For colder temps (an overnight in the mid-upper 20's) I used this with a 20-degree bag (thermolite bag) and was a little warm with the same sleepwear. Any colder though and I would use it with a 3/8" ensolite pad (mummy cut). I will say that the ensolite pad and XFrame combo is extremely comfortable and my favorite sleeping setup currently. Even more impressive is that this pad can be filled with Klymit's NOBLE TEK Argon insulation, rendering it the most efficient pad insulation available on the market (research it - the science is compelling)

I slept on it this Summer while beach camping (though the ground below was rough) and it outperformed my Basecamp 2" in terms of comfort. I used a fitted pad sheet over a rectangular 20X72 ensolite pad to sandwich the X Frame and hold it in place, then used a UL blanket — a great summertime setup.

I did try this another time outside my tent on a thin groundsheet, with protruding rocks and small pinecones, and did occasionally feel them in the loft pockets when I moved around — not recommended. This pad will not perform well in those conditions. It also is not intended as a seat in the backcountry for the same reason. I also tested this pad in just shorts, fully inflated plus one air pump shot. I slept on the tile in my kitchen with only a sheet covering me, figuring that the cold, hard floor would expose any design flaws in the skeletal design. I slept on my back to start, but without a mummy bag to hold my arms in place on my chest, my arms ended up on the cold floor. I turned on my side and didn't experience cold spots from ground contact again. I did welcome the coolness in the voids since it was warm that night in my house. I did not experience cold spots when used with a sleeping bag on any real camping trips. However, if I had loose skin, excess fat, or a big torso, I might have touched the ground in the pockets. But I was comforatble thhe rest of the night.


This pad is very well constructed. The welded seams are impeccably executed — the best welding work I've seen. The fabric is extremely durable, having stood up to nights out on the rough ground of the San Gorgonio mountains without a puncture or scratch. I was concerned at first, but with the excellent repair kit, I got over that quickly. I did not have to use the kit.


I applaud Klymit for thinking outside of the rectangle and challenging conventional thought. This pad is as light as it gets, and stands unchallenged in the comfort to insulation to weight ratio — IF it fits your body type. Make sure it works for your build and you won't be disappointed.


thetentman RETAILER

I use mine inside the sleeping bag. Never going back to the other pad.

3 years ago
thetentman RETAILER

better than sliced bread

3 years ago

The Klymit Inertia X Frame pad is an exceptionally…

Rating: rated 4 of 5 stars
Source: received for testing via the Trailspace Review Corps


The Klymit Inertia X Frame pad is an exceptionally lightweight pad designed for long distance hikers, bike tourists, or other backcountry adventurers who want light equipment, but are seeking a level of comfort different (thought not necessarily greater) than a closed cell foam pad provides. It's incredibly compact, easy to inflate (though not to deflate), and reasonably comfortable, though might not be as comfortable for the very short or very tall. This pad is best for light hikers, bikers, and runners who want to minimize weight and volume.


  • Easy to inflate (4-5 breaths! + 10-20 pumps of the bulb)
  • Reasonably comfortable
  • Light
  • Very compact


  • “Voids” make sizing important. Shorter folks beware!
  • Cold spots seem to coincide with voids
  • Leaking is possible with bulb attached.
  • Difficult to maintain high pressure.
  • Difficult to deflate

The Klymit Inertia X Frame sleeping pad deflated.

Ease of Inflation

This pad is a snap to inflate. At sea level in both cool (36°F) and hot (80°F) temperatures, 4-5 robust breaths of air into the inflation/deflation valve inflate this pad. At this point, instructions dictate using the detachable bulb to “top” it off until it's quite firm. This requires 5-20 puffs of the bulb.

Out of curiosity, I attempted to inflate the pad with the bulb alone. Not recommended: 275 squeezes later I lost count. Also, make sure to detach the bulb after topping the pad off. Leaving it on created a slow-leak situation for me one night, and I woke up with the pad nearly flat. When pumped up to high pressure, the pad did seem to lose a bit of air overnight. Certainly not enough to make it “soft,” but enough air seemed to diffuse through the material so that it required another 3-5 pumps from the bulb in order to firm up again.


The Klymit Inertia X-Frame sleeping pad inflated

Ease of Deflation
Popping the mouth valve open releases a torrent of air that deflates the pad about 80 percent. Here, things get a bit tricky. I tried my standard deflating technique (folding in quarters and sitting on it), but this didn't work well. Instead, Klymit recommends that you fold it in half lengthwise and roll it towards the bottom. The mouth valve requires a substantial degree of pressure to release the air, and it took a bit of trial and error to get the pad to deflate fully.

Mouth valve


I tested this pad at 36°F, in the mid 40s, and at 65°F, all with the same EMS Velocity 35 men's sleeping bag in a Henry Shires Tarptent Cloudburst 2*. On the 36-degree night, I wore a full set of EMS Bergelene Base Layers, a thin synthetic cap, thin synthetic gloves, thin liner socks and wrapped my The North Face DIAD Jacket around my feet. I slept well that night, but did notice some cold spots that seemed to coincide with the voids in the pad.

Kylmit claims these voids provide the opportunity for the sleeping bag's insulation to loft underneath you, but I theorize that this doesn't occur with sleeping bags that don't have a lot of loft to begin with, like mine! I did sleep through the night, and didn't shiver, but certainly noticed these colder areas.

During the nights in the 40s, this pad preformed admirably with the same setup, minus the hat, gloves, and jacket-around-the-feet. At 65-70 degrees, the cool spots were nearly a blessing! Having ridden my bike hard for more than 20 miles to get to my favorite local camping spot, I was clammy and a bit warm when I went to bed.

The Velocity 35 only has a quarter length zipper, but I was still cool enough to get in. The ventilation provided by these voids meant that I woke up drier and less sweaty than when I retired. With my ordinary closed cell pad and the singe-wall tent, I ordinarily would have awoken quite clammy.

Klymit inflation bulb


This pad isn't less comfortable than a closed cell pad, its nearest cousin in weight, but it isn't more comfortable either. It is “differently comfortable.” The pad is 73 inches long. At 5'7", I'm 67 inches long. This small difference in size led to some minor discomfort during the night, as I shifted about and different parts of my body aligned with the inflated portions (felt great) and the voids (not so great).

When my body was aligned with the inflated portions, this pad was quite comfortable. When I was not aligned, this system was less comfortable. If your height differs from this pad's length by more than six or so inches, this problem might affect you.

It occurred to me that this problem might be remedied by placing the pad inside my sleeping bag, and when I'm able to purchase a bag that will fit this pad, I'll report back.

It's worth noting that this pad did not skid around the slick nylon floor of my tent, a very welcome result.

My pack, ready for my last test of this pad: bike camping!


This pad is supremely packable! Deflated and wrapped up in the storage sack, it is barely 8 inches long and 11 inches in circumference. Unpacking was an eerie experience, as it appeared that I had forgotten my sleeping pad until it emerged, so small as to be nearly invisible inside my pack!

My pack during testing on the International Appalachian Trail


Stuff sack, pad, bulb, and repair kit weigh 11.1 ounces together. The pad and the bulb alone, the minimum useful configuration, weights 10.5 ounces and the pad along weighs 9.2 ounces.

Testing Conditions

I tested this bag camped north of Baxter State Park in late May, in temperatures down to approximately 36°F, in Mid-June in the same area, while backpacking a segment the International Appalachian Trail, and in early July in southern Maine, during a sub-24-hour-adventure bike camping trip.

* The author is employed by an organization that is the recipient of donations by Tarptent, and that provided this Tarptent to the author as a gift four years ago.


275 pumps later... Woah. You have more patience than I do by a long shot. So, I take it that this would not be the pad for winter treks due to the voids in the design. I wonder how effective a closed cell(blue) pad would be under the Inertia for cold weather travel. Nice review Seth.

3 years ago

We're on the same page here. I think putting this over a closed cell foam pad would be a powerful combo. I can't wait to try it.

3 years ago

Hi fellas. This could be a great pad for Winter treks IF you're sleeping bag is high loft (to fill the voids) and you use Klymit's ARGON insulation. One cartridge and valve would add a mere 3 oz to your packweight and would last you for at least one trip. If you forgoe the NOBLE-TEK Argon insulation and use this with another UL pad (including an Ensolite pad) you would have a real strong Winter performer.

3 years ago

Great point Xterra! I'm considering a follow-up review for this winter.

3 years ago

This product is lightweight, and is a good choice…

Rating: rated 3 of 5 stars
Source: gift


This product is lightweight, and is a good choice for the right person.


  • Lightweight
  • Tough
  • Blows up fast


  • Not one sized fits all
  • Fits men's bodies who are average sized
  • Hard to fine tune air

This is really a very good product. But it really is a niche product. This pad is about 6' long, and because of its size and design, the padding is located at the "sweet spots" of head, shoulders, hips, and feet. Well, as an average sized woman, this was not a good choice.

While that is not the product's fault, the pad is not really good for all hikers.

I love the very lightweight part, and that it is tough.

But I was very frustrated that I have to sleep within only the sweetspots' locations, and I "bottomed out" while sleeping on my side, especially at the shoulder.

I love that the pad blows up very quickly. But I found that once it was blown up, I could not "fine tune" the fit. I will not be using this pad next season.

But if Klymit ever makes a similar pad that is thicker and designed for a shorter person's height, I would take a long, hard, serious look.

But for now, I need to find an average sized man who could use this pad.


This pad is designed to go INSIDE the sleeping bag!

Rating: rated 5 of 5 stars
Source: bought via a "pro deal"
Price Paid: $60?


This pad is designed to go INSIDE the sleeping bag! I never roll off this pad!! At 9.1 ounces, this pad disappears into my sleeping bag stuff sack until called upon to insulate my chilled core. The pad is built with gaps where the body does not contact the ground, these gaps allow the insulation in ones sleeping bag to sustain full loft, keeping the body warmer!


  • used within the sleeping bag
  • inflates in 3 breaths
  • comes with hand pump
  • excellent for hammock use
  • can be deflated and stuffed while still in sleeping bag
  • not just ultralight, but ultra compressible


  • requires some thinking/experimenting
  • not ideal for bigger people

The last thing I want to do after mile 10 is to huff and puff into my sleeping pad. I mean, I am huffing and puffing anyway, but mostly just to remain conscious.  I have several sleeping bags that, when used at high elevations, after an exhausting day, and with chapped lips, the mouth-to-valve connection is beyond my abilities.  

Not so with the Inertia X Frame. This 9.1 ounce beauty inflates with just three breaths, really, three! What is better is that those breaths can be fairly relaxed, as they need only supply the bulk of the air. Once the valve is tightened the user simply turns to the other top corner of the pad, inserts the ball pump, gives twenty or so squeezes, and the pad is perfectly firm for those extra cool evenings or extra hard shelter platforms.  

Even better, after that midnight tinkle, once you return to your cozy sleep system and find that the air has condensed during the night, just click the ball pump in place again, squeeze, squeeze, squeeze, and ta da, the pad is once again firm without removing it from the bag, leaning over to huff and puff, or disturbing your tent mate with other pad adjustments.

The pad has lasted me through years of trips in and around the high desert of Arizona.  It continues to serve me well here, in New Hampshire. As the pad spends all of its time in my sleeping bag, during use and while in storage, it is never subject to puncture or abrasion.

The pad does not offer three inches of loft. It is not filled with Primaloft, feathers, or magic. It simply holds air which keeps the ground from stealing all of my hard earned heat.  For that purpose, the Klymit pads are exceptional!  -MK 


Very lightweight and small. Perfect for backpacking…

Rating: rated 4.5 of 5 stars
Source: bought it new
Price Paid: about $50


Very lightweight and small. Perfect for backpacking and remaining off the ground while comfortable.


  • Lightweight
  • Compact


  • Width a bit small
  • Susceptible to leaks

I really like this pad. If it holds up over time, even better! My only concern is that of structural integrity. I'm not sure about having to haul a repair kit with me, even if it is small. (Although I am getting over it, because even with the repair kit, it is so much lighter and smaller than all other alternatives.)

I purchased it online for about $50, which is a bit pricey, but still acceptable, given the pleasures of a good night's sleep in the bush.

It reduces down to slightly smaller than a red solo cup. Or, put another way, slightly shorter than a soda can, but also slightly fatter.

Weight is 298 g with the stuff sack, or 10.51 oz.

The design is marketed towards helping your sleeping bag retain loft due to the cutouts in it (as well as weight reduction).

It comes with the already mentioned repair kit and an inflation bulb (like the thing the doctor squeezes when taking your blood pressure).

It takes about 8 breaths to fill, after which you can use the bulb to increase the air pressure. I am not sure you need to bring the bulb, as when I used it, it just over-inflated the mattress to the point of me sliding on top of it rather than sinking down into it.

Leave the bulb at home and drop a few grams from the weights listed above.

Overall, a great product so far (5 nights in the field). I'd buy it again.


Nice change from the old Therm-a-Rest 1 inch pads…

Rating: rated 4 of 5 stars
Source: bought it new
Price Paid: $85


Nice change from the old Therm-a-Rest 1 inch pads and perfect for those ultralight guys who want the lightest.


  • light weight, perfect for the thru hiker crowd


  • not for real long nights

I have used this five nights and at first very impressed but after my last night, which was very cold and long. I wished for my full mattress that is 2.5 inches thick. Still think it would be great for those people concerned about fastpacking and weight.


The great news for long, cold nights is that you can use Klymit's NobleTek Argon gas for insulation and really drive up the insulating capabilities of this pad. The Klymitizer nozzle with full cannister tips the scale at 3.5 oz. Combine Argon's superior insulating capabilities (vs any other option, including down) with this pad and a great sleeping bag and a prolite pad, and you have an ultralight pad system for about 2 pounds...

3 years ago

...that happens to compete with 4 season pads weighing much more.

3 years ago