Field Test Report: 
Therm-a-Rest ProLite 3 Short Sleeping Pad

Date: April 19, 2004

Product Description
(Information assembled from web research by the author) For 2004, Therm-a-Rest has reorganized and redesigned their line of outdoor sleeping pads. The Fast & Light Series (6 different pads) is the lightest and most compact. Of these, the ProLite Pads represent the biggest innovation. To make the pads lighter, the polyurethane foam core has been die cut into a matrix of four-cornered stars. The lighter core and lighter/tougher top and bottom fabrics make the ProLite 3 Pads 28% lighter than their predecessor UltraLite Pads. The ProLite 3 Short (¾ length) at 13 oz (370 g) is the lightest of the ProLite Pads and is 5 oz (142 g) lighter than the UltraLite ¾ it replaces.

Intended uses are 3-season backpacking, mountaineering, bike camping, and boat touring—wherever minimum weight and compactness are desired features. The ProLite’s orange top makes it easy to distinguish from the bottom, which is charcoal-colored. The top has a slip resistant finish so a sleeping bag will stay put. The bottom has a fine grid of gripper dots to minimize sliding on a tent floor or groundsheet. The Pad’s top/bottom edges and corners are rounded. A plastic valve is used on the ProLites, which is easier to use and more reliable than the previous metal valves. The pad has a lifetime warranty from Cascade Designs.

Test Locations and Conditions
I have used the pad on 4 outings so far, a 2-day car camping trip in New Mexico,  two 4-day backpacks in Southeastern Utah, and a 2-day backpacking trip in New Mexico. The NM trips were in badlands country at 6200 ft/1890 m elevation with 60-65 F/16-18 C daytime temperatures and 32 F/0 C nighttime temperature. The first UT trip was in canyon country at 6000-6400 ft/1830-1950 m elevation, 70-75 F/21-24 C daytime temperatures, and 40-45 F/4-7 C nighttime temperatures. The second UT trip was also in canyon country with similar daytime temperatures; nighttime temperatures were 27 F, 48 F, and 49 F (-3, 9, and 9 C) There was no precipitation during these trips and very little wind. The ground surface each night was quite smooth with few, if any, sharp objects under the pad.

How the ProLite Pad Was Used—On the first trip I slept in a 2-person backpacking tent with a urethane coated nylon floor. On the second outing I slept in a Tarptent with a silnylon floor to which I had applied 1 in/2.5 cm strips of silicone at 10 in/25 cm intervals to reduce slippage. On the third and fourth outings I slept on a #14 soft Tyvek groundsheet under the stars. On the latter 3 trips I purposefully chose sites that had a slight slope and slept with my feet downhill. The sleeping bag used was a Marmot Helium with a Pertex microfiber shell.

Field Test Report
Usability—The pad does not self-inflate like previous Therm-a-Rests, but it inflates quickly by mouth--only 5 full breaths required. It deflates just as easily. When deflated it is very compact and packs easily. I like the orange top color that makes it easy to see, especially in dim light. The bright orange color is no problem for me because the pad is normally covered by a tent and sleeping bag. I also like the fact that the top and bottom are distinctly different colors so there is no question about which side is up. The width of the pad is sufficient so I can turn over without moving off the pad.

Comfort—My bony body needs an inflatable sleeping pad in order to get a good night’s sleep in the backcountry. I found the ProLite pad to be quite comfortable either fully inflated (hard) or softened slightly by letting a little air out. The adjustable comfort range is from full inflation (hard) to the point where my hips begin to touch the ground (soft). I would rate the comfort level at a 7 on a scale of 10. A thicker Therm-a-Rest would obviously be more comfortable, but considering the weight factor, the ProLite does an excellent job with minimal weight. A closed cell foam pad weights about 6-10 oz/170-283 g (depending on size), but it is murder on my hips. So the ProLite 3 Short pad at 13 oz/370 g provides a lot of extra comfort at minimal extra weight.

Slide Resistance—The top surface holds a sleeping bag in place quite well. The amount of resistance seems to be just right, so I can turn over without moving the pad. The bottom surface did not easily slide on a polyurethane coated nylon tent floor. It slid easily on plain silnylon, but stayed in place nicely in the Tarptent with anti-slip strips of silicone painted on the silnylon floor. The top surface of the pad resists sliding on silnylon more than the bottom surface. The pad also did not slide on a Tyvek groundsheet. I had no problems with sliding downhill on the slightly sloped surfaces I slept on.

Use As A Pack Backpad—Folding the pad lengthwise then into thirds (6 layers) fits best in the sleeping pad pocket of my GVP Gear G4 pack. In this configuration the pad provides excellent back padding. When I use the pack for a day hike from camp I leave the pad in to provide a back pad. The ProLite 3 does not provide much structural rigidity for my frameless pack.  

Durability—The weight of the top and bottom fabrics appears to be a good compromise between durability and lightweight. Folding the pad as described above puts a permanent crease in the pad, which disappears when the pad is inflated. So far the crease does not seem to damage the pad.

Insulation—I did not use the pad on cold or frozen ground conditions, so I have nothing to report. On 3 sub-freezing nights I did not have any problems with being cold on the bottom side.

Water Resistance—I placed a spoonful of water on the top surface and found that the fabric is easily wetted, as is the case with previous Therm-a-Rests. The same test revealed that the bottom surface is highly water resistant.

Suitability for Ultralight Backpacking—The pad at 13 oz (370 g) is delightfully light. It has a good balance between durability and lightweight. However, many ultralight backpackers would favor an even lighter version of this pad. “Three-quarter length” (47 in/119 m) is an arbitrary length for a sleeping pad; why not a “half-length” pad? Therm-a-Rest should consider offering a minimalist version that is sized to pad only the torso area. Weight could be further reduced 2-3 oz (57-85 g).

My Expectations For The ProLite 3 Short Pad
Following is an update on my expectations for this pad, stated as hypotheses.

• The ProLite 3 Pad will be equal to or more comfortable than its predecessor the Therm-a-Rest Ultralight pad, with less weight. (True.)
  
• The ProLite 3 will be significantly more comfortable than a closed-cell foam pad to justify carrying the extra weight. (True, it weighs only 4.7 oz/133 g more than a RidgeRest ¾ length pad, and is a lot more comfortable.)
  
• The ProLite 3 Pad bottom surface will not easily slide on silnylon or other slippery materials. (True with qualification. It slides easily on silnylon, but the problem can be eliminated by painting strips of silicone on the silnylon.)
  
• My sleeping bag will not easily slide off the ProLite 3 Pad. (True)
  
• The ProLite 3 Pad will work well as a backpad in my G4 pack. (True)
  
• The ProLite 3 Short Pad will work well in a Therm-a-Rester (a fabric sleeve that converts a sleeping pad into a camp chair). (Not tested yet.)
  
• The ProLite 3 Pad will be adequately durable for normal use in a variety of terrains, climates, and surfaces. (True so far.)
  
• The ProLite 3 Pad will perform equally well in a variety of sleeping systems (bivy, tarp, Tarptent). (True so far.)
  
• The ProLite 3 Pad will provide adequate insulation from cold/wet ground. (True so far.)
  
• The ProLite 3 Pad will perform well as a component of an ultralight backpacking system. (True, but a “half length” pad would work even better.)