Thursday 12 April 2012

Therm-a-rest NeoAir - comfortable but unreliable.

When Therm-a-rest released its NeoAir in 2009 it was a revelation. For the first time you could have it all. The NeoAir was amazingly comfortable, but also light and with a tiny packed size. I liked what I saw. This was the future of camping mattresses. Initially demand was so high that I struggled to find one in the UK, but on the 2009 TGO Challenge I finally got to see one. It was certainly comfortable but looked a little fragile, could it last a long hike? I wasn't so sure. The following year I hiked the Arizona Trail. This trail is known for being brutal on kit and that proved to be true. Inflatable mattresses were not recommended. Being a sensible hiker I heeded those warnings and took a standard piece of closed cell foam. This was light and reliable but also plain uncomfortable when laying on the sun baked mud and rock that makes up a lot of Arizona. During that hike I met Kimberlie Dame and she had bravely used a NeoAir for the entire hike without any problems. Convinced that with a little care they could be robust enough, and sick of sleepless nights and pain I finally tracked one down. The deal was done and it preformed brilliantly for the rest of that hike. It changed the way I camp forever.

However... shortly after the AZT Kimberlie's NeoAir started to slowly deflate during the night. No matter how hard we tried we could never find the source of that leak. Dipping it underwater, like you would with a bike inner tube revealed nothing, yet every night it would slowly deflate. With time the situation was clearly deteriorating and secondly my NeoAir was also now suffering the same problem. Not happy I started to investigate further… The bath was filled and the NeoAir submerged. Nothing! No visible leaks! How could that be? Knowing that there had to be a leak somewhere I got Kim to stand, full weight, on it. With this pressure the thing suddenly erupted in a stream of tiny bubbles from seemingly EVERYWHERE! There were hundreds of tiny pinhole leaks.

Looking deeper all the leaks were on the lower silver material, none on the yellow upper or from the side seams. Amazed that we could have possibly punctured the fabric so many times I marked them all. What I found was interesting. All the leaks occurred on a baffle seam, none could be found mid tube, or anywhere else. This just didn't make sense to me. If they had been punctures from normal use then I would have expected them to be randomly dotted all over the fabric or grouped in a particular area. Could this be a design fault with the NeoAir or its materials? After careful examination of both NeoAir's it was clear to me that this was the case.

Kim's was opened to see what was going on inside. The construction is interesting with a reflective layer sandwiched between two layers of nylon. This nylon shell is coated in a heat sensitive adhesive which holds everything together and probably keeps the nylon airtight. Keeping the NeoAir in shape and reducing internal air movement are baffles which are clearly visible from the exterior. These are just like the ones found in your sleeping bag. The problem appears to be where the baffles are glued to the outer shell. It's hard to say exactly what's going on because nothing was visible under inspection. What I believe is happening is that over time these baffles are pulling away from the shell, perhaps removing some adhesive which makes the shell no longer airtight. This doesn't appear to be a big problem until the mattress is pressurised by lying on it. Over time, more and more separation occurs and that sinking feeling happens quicker.

What this means to you. Though my NeoAir failed much later after Kim's, they both failed  after approximately the same amount of trail time. Disappointingly this was around 2 months of continuous use, or only 60 nights. For a thru-hiker this is a real problem and I would no longer take the lightest NeoAir's on a such a hike. I guess for the average hiker 60 nights equates to 2 or 3 years of use. For them this is perhaps not such a big problem. NeoAir's do come with a lifetime warranty and could be easily replaced between hikes, but that's not much use for thru-hikers! I still use the Therm-a-rest NeoAir range as my primary camping mattress but now take a modified Trekker (shortened) for thru-hiking and a full length All Seasons for winter use. Both of these use different base shell materials and so far have been reliable. Therm-a-rest have also just replaced the original NeoAir range with the Xlite. I have not had the chance to see or test one yet but hope that improvements have been made to the fabric. Kim is taking one on her PCT hike this year so I shall be keeping an eye on how long that lasts.