Initial Report: Therm-a-Rest ProLite 4 Short Pad

Tester:  Rosaleen Sullivan

Age: 53 years

Gender: Female

Height: 5’ 9” / 1.75 m

Weight: 190 lb. / 86 kg

E-mail: rosaleen43 (at) aol (dot) corn

Home:  Eastern MA, USA

Date:    February 6, 2004/Formatting errors corrected and re-uploaded February 22, 2004

Tester Background

I have done family car camping from my childhood, using many shelters from a tarp through a travel trailer. The backpacking bug bit when I went along as a driver/chaperone for my oldest son’s Boy Scout Troop. After learning to backpack by the old Troop methods, I decided about age 50 that there had to be a better way. I’m gradually lightening up, and I do most of my hiking and backpacking during weekends in New England. Additionally, I have been lucky enough to experience hiking to the bottom of the Grand Canyon and a 110 mile (177 kin) stretch of the Appalachian Trail from Pennsylvania to northern Virginia. My preferred gear at this time is a Hennessy Hammock for shelter, an alcohol or solid fuel stove, home-dehydrated foods requiring minimal preparation and cooking on the trail, and the least amount of additional clothing and gear that I can feel comfortable carrying.

Product Information

Manufacturer:  Therm-a-Rest.com

URL:    http://www.thermarest.com

Year of Manufacture: 2004

MSRP:  NA

Listed Weight: 17 Oz (482 g)

Weight as Delivered: 15 oz (425 g) weighed on a scale at a local business

Product Description

The Therm-a-Rest ProLite series is a group of self-inflating camping mattresses.  Within the family, there are choices in widths, lengths, and thicknesses.  The ProLite 4 is the thickest. I have chosen the short model in the narrower of the two available widths in order to maximize padding while still minimizing weight. The ProLite 4(S) measures 20 x 47 in (51 x 119 cm), by about 1.5 in (4 cm) thick, and weighs about a pound. My tiny kitchen scale bottomed out when I tried to weigh the mattress in the manufacturer’s package, so I took the mattress to a local hardware store that also serves as a commercial shipping depot.  Out of the package, the ProLite 4(S) weighed 15 oz (425 g) on their scale.  I will weigh it again on another scale during a later phase of testing, but for now, it seems to be a bit less than the package-listed weight of 17 oz (482 g).  I’m not going to complain if gear is lighter than anticipated!

The top surface of the mattress is orange fabric.  The manufacturer lists it as polyester, and it has the grid look I associate with rip stop type fabrics.  The die cutouts in the middle layer of open cell urethane foam are visible from the somewhat translucent top.  From the outside, the type of foam is not apparent, but I infer open cell by the fact that it is self inflating.  Additionally, I’ve seen the sample cutouts of older models in stores.  Those were open cell foam on the inside.  I have no reason to doubt that the foam is urethane, as stated on the package.  The bottom of the mattress is listed as nylon and is black with tiny raised gray dots.  I have to believe the textured undersurface is intended to reduce slippage as the pad is used.  I couldn’t tell that the texture had much anti slip effect when I briefly lay on top of the pad sandwiching a plastic trash bag between the pad and a hardwood floor.  The indentations from the die cuts are visible from the back of the pad, but the darker fabric doesn’t allow me to “see” them.  The mattress has a black twist valve that maintains inflation or deflation.  The valve is hard and I assume that it is made of plastic.  I see no evidence that it is a plastic cap over a metal valve and am not comfortable with the idea of trying to remove it or take it apart for further examination.  This mattress also has rounded corners which may also shave a bit off the weight.  It doesn’t appear to be “tapered.”  Maybe tapering is more evident in the longer models.  The package also lists a urethane coating.  I suspect the inside of the top and bottom layers have this urethane coating to help the mattress be air tight, and because of the air impermeability, also water proof.

Initial Impression

The mattress arrived in a small box while I was at work, January 30, 2004.  When I picked up the box, it felt light enough to be empty, but sure enough, there was this tiny roll inside.  After trying to weigh it, I took the wrapper off the rolled mattress.  I had it only partially out of the plastic wrapper when I started hearing air “whooshing’ into the mattress.  This was a bit of a surprise, as I expected the mattress to be slow to inflate after deflated storage.  I was also struck by how light it felt and how much thicker it seemed compared to my older Therm-a-Rest mattresses.  I knew it was going to be thicker, but I was taken aback when I laid an UltraLite short next to the ProLite short mattress.  The new one appears to be twice as thick.  It was cold on its initial fill, but the mattress seemed inflated within about 3 minutes.  I laid on it on my hardwood floor just to check it out.  I could still feel my hip on the floor while on my side, and will need more padding to sleep on my back with this.  The padding may be a sack of clothes under my legs to allow my lower back to relax and flatten a bit.  I’ll be determining this during testing. Intending to put the mattress away before attending to some chores, I opened the valve to flatten the pad and was pleasantly surprised to hear more air entering the mattress.  Apparently, just a bit of body heat helped the mattress expand more.  It seems that in order to reach the manufacturer stated 1.5 in (4 cm) thickness, I may need to add a puff or two of air.  This is another thing I’ll be looking at during the test.

Of course, after looking over the mattress and giving it a cursory test, I bothered to notice it actually had printed instructions that had fallen on the floor.  (I don’t actually PLAN to be the “When all else fails, read the instructions” type!)  The instructions say to inflate the mattress and let it sit overnight before use so that it can achieve full inflation.  The instructions were easy to read, and recommended that a repair kit should be purchased and carried.  I may look around to see what multi use item I can carry that might also repair the mattress, in a pinch.  We have had some Therm-a-Rests for as many as 15 years.  The only problem we had with any of them was that one developed a leak around its (formerly used) brass valve.  The upgrade kit took care of that.

At the end of a week, I can still see the center fold line, and did need to give it a couple of puffs to get the mattress to the 1.5 in (4 cm) thickness.  I have to say it is far more cushy feeling than any of the earlier versions of standard Therm-a-Rests that I’ve used.  My husband and one of our sons, who are familiar with the old Therm-a-Rests, were “bug-eyed” at the softness and lightness of this mattress.  Fortunately for me, they don’t camp or backpack much these days, or I may have had trouble getting the ProLite away from them to use it myself!

Test Plans

I live in Eastern Massachusetts, on the coastal plain.  Testing will start in or near my backyard as I acquaint myself with the comfort range of the ProLite 4.  Before actual trail use, I need to know if I will find the mattress to be enough of cushion for my specific needs and warm enough for anticipated temperatures.  “The Princess and the Pea,” a children’s tale about a princess who could not sleep on a stack of mattresses because there was just one pea under the stack, could have been written about me.  I do not sleep unless I am comfortable.  Period.  I have to be warm enough, and the surface has to be firm, yet still cushioned.  Otherwise, I will aggravate chronic hip bursitis or back spasms that have plagued me for more than a decade.  Outdoor sleeping comfort is a tall order and nearly caused me to give up backpacking until discovering Hennessy Hammocks.

I want to test the mattress by itself on a wooden surface, similar to a shelter, on a grassy or leafy surface, as one might find trailside, and in my hammock.  Additionally, I want to try it combined with other pads, both closed cell foam and air mattresses.  Closed cell foam is a great insulator, but I have not found it to provide enough cushioning that I can sleep on it.  Generally, air mattresses that are inflated enough to prevent my hip from contacting the ground are too hard to be comfortable and I end up unable to sleep due to hip pain or back spasms.  I want to see if the ProLite provides the necessary comfort to make sleeping on the ground or in a shelter a possibility for me.  Testing will include using the mattress in my hammock, a tent, and a silnylon fly.

As I determine what combination works for me, I will move from the safety of my yard to local trails, including the Midstate Trail that winds through Worcester County in Massachusetts, and further, to the Appalachian Trail, mostly in Massachusetts and Connecticut.  Near the end of the testing period, I will take the ProLite with me on a trip to Yellowstone Park in Wyoming.  Locally, I expect the terrain to be mostly flat to rolling hills with an occasional mountain.  The highest mountain in Massachusetts, Mt. Greylock is only about 3500 ft. (1067 in), so I don’t anticipate noticing any altitude effects in the mattress.  In Yellowstone National Park, I expect to experience altitudes in the 8000 to 10,000 ft. (2400-3000 m) range.  I will report on any noticeable differences between lower and higher altitudes as they might affect the mattress.  As far as testing insulation value, I think it is safe to anticipate a wide range of sleeping temperatures.  We have had many very cold nights in the Northeast part of the USA this winter.  I’m not interested in sleeping outside in temperatures much below 15 F (-9 C).  That is just too cold for me.  Things seem to be warming up a bit, so I’m hoping for many nights between 20 and 40 F (-7 and 4 C) for the first two months of field testing, increasing to daytime temps between 70 and 90 F (21 and 32 C) with cooler nights into July. Comfort and insulation, along with durability will be my first points of focus, and water resistance and slipperiness on various surfaces will also be considered.  The air valve doesn’t turn as smoothly as I’d like and I will see whether or not that loosens up or becomes a problem over the course of the test.

Likes So Far

Cushy

Very light

Easy to inflate

Dislikes So Far

Plastic air valve seems to drag during opening and closing

Doesn’t seem to flatten to original packed size. (Practice issue?)

Respectfully submitted,

Rosaleen Sullivan