Articles (2020)

Introduction

When we saw Sierra Design’s new Assailant tent at the Winter 2007 Outdoor Retailer Show, we were impressed by its design and breathability rating. The fabric is Sierra Designs’ DriZone, which is a two-layer polyurethane laminate with a breathability rating of 28,000 g/m²/24 hr and waterproofness rating of 18,000 mm, which are outstanding numbers. The breathability rating is equivalent to that of eVENT fabric measured by the same test. How did the Assailant perform in our field tests, and how practical is a one-person tent for winter camping?

What’s Good

• Lightweight, strong aluminum poles
• Fast, easy setup
• Easy entry
• Sufficient room for one person plus gear
• Small footprint
• Four-way ventilation

What’s Not So Good

• No vestibule or beak to protect the entry
• Low headroom
• High condensation in cool wet calm conditions
• Expensive
• Not a good winter tent

Specifications

Year/Manufacturer/Model	2007 Sierra Designs Assailant
Style	1+ person single-wall breathable fabric freestanding tent with floor, 1 door, no vestibule
Fabrics	Body is 40d ripstop nylon DriZone two layer laminate, 2.1 oz/yd2 (72 g/m2) with a waterproofness rating of 18,000 mm and breathability rating of 28,000 g/m2/24 hr; floor is 70d nylon taffeta (3000 mm)
Poles and Stakes	Three pre-bent DAC Featherlite NSL 8.5 mm
Dimensions	Front width 82 in (208 cm), maximum width 93 in (236 cm), depth 47 in (119 cm), height 30.5 in (77 cm)
Packed Size	About 18 in x 6 in x 6 in (46x 15 x 15 cm)
Total Weight (As supplied by manufacturer with all included items)	Measured weight 3 lb 9.8 oz (1.65 kg), manufacturer specification 3 lb 11 oz (1.67 kg)
Trail Weight (Includes minimum number of items needed to erect the tent)	Measured weight 3 lb 6.5 oz (1.55 kg); includes tent body, three aluminum poles, and eight stakes; manufacturer specification 3 lb 3 oz (1.45 kg)
Protected Area	Bathtub floor area 22.5 ft2 (2.1 m2), no vestibule
Floor Area/Trail Weight Ratio	6.61 ft2/lb based on 22.5 ft2 floor area and weight of 3.4 lb
MSRP	$319

Performance

The Sierra Designs Assailant is a one-person, four-season, single-wall, freestanding tent made with waterproof/breathable fabric. It’s designed to provide all-weather shelter for one person plus gear. Many mountaineers prefer a tent of this type because it has a small footprint, is fast to set up, is very weather-resistant, and has room inside for gear.

Sierra Design’s DriZone fabric is a two-layer laminate with a ripstop nylon face fabric and a thick layer of polyurethane on the inside. All seams are taped. Their breathability claim for this fabric is extraordinary: 28,000 g/m²/24 hr (using the JIS 1099 test method). For comparison, three-layer eVENT, which is the undisputed (but tragically unavailable) standard for waterproof/breathable tent fabric, has a breathability rating of 27,826 by the same test. We don’t have any means to test those numbers, but we were curious to test the Assailant in the field to find out how well it performs.

The Assailant uses one long diagonal pole plus two shorter extender poles. The DAC Featherlite NSL aluminum poles are pre-bent and easily inserted into pole sleeves that have a dead-end pocket at one end and grommet at the other. Setup is fast and simple; I timed it at 2.5 minutes. Eight stakes are required for a secure pitch, which includes two guylines on the ends.

Ventilation is via three vents (two on the ends and one on the back) plus the tent door, so the Assailant has 4-way ventilation. The vents have hold-open rods that are operated from the inside. There is no vestibule to protect the entry, but it is possible to open the top of the door about 4 inches without rain or snow entering the tent (assuming it’s not wind-blown).

Field Report

In my field testing, I was able to evaluate the Assailant in two snowstorms, an all-night rain, and cold temperatures down to 14 °F, but only minor winds.

With only 30.5 inches of headroom, the Assailant forced me to do everything while lying down. I could sit up in the center, but my head bulged the top of the tent. For me, the confinement was not my first choice for living conditions, especially on long winter nights.

The first snowstorm I experienced was just a couple of inches, but enough to point out one serious limitation of the Assailant – snow is held on top of the tent by the two pole sleeves. The second snowstorm I experienced in the Assailant at 9700 feet dropped a foot of snow overnight. It was a constant (and sleepless) process to heave the snow off the top of the tent from inside. The tent’s construction is quite strong to support snow, but there is a distinct risk of the tent suffering serious damage if it gets overloaded with snow, as it might if left set up all day in a snowstorm.

In dry and warmer conditions, I kept all four vents (including the top of the door) open for nighttime ventilation, and the Assailant stayed dry inside. On really cold nights, with all vents open, I had some frost on the tent walls near my head (from my breathing) but the rest of the tent was dry. Overall, the Assailant performed well in dry conditions.

However, on one rainy night with a low of 38 °F, and during the snowy night described above with a low of 28 °F, I had copious amounts of condensation inside the tent. In both cases there was little air movement and not much of a humidity gradient, so the moisture could only condense on the cold tent walls. In cold temperatures, the tent’s small interior volume and the user’s close proximity to the tent walls contribute to the condensation problem. Unless there is good air circulation through the tent, moist air will contact the cold tent walls and condense or freeze.

Assessment

As far as design and ergonomics, the Sierra Designs Assailant tent is well designed. It is easy to set up in locations with restricted space. Entry is from the side and there is sufficient room inside to accommodate one person plus gear. It’s made of high quality durable materials.

The DriZone fabric has a relatively thick polyurethane coating on the inside. Polyurethane is very durable so the coating stretches with the tent walls and won’t be easily damaged with normal use. Obviously, there are limits to this durability.

Polyurethane’s hydrophilic properties enable the DriZone fabric to transfer moisture effectively. Moisture is absorbed by the polyurethane, diffuses through the membrane, and then evaporates from the outside surface. Driven by vapor pressure gradients, it can be a slow process at lower temperatures because it involves two phase changes of water (vapor to liquid to vapor), and in no way compares with the ability of gas-permeable eVENT fabric to transport water vapor directly. Regardless of the claimed breathability specification for DriZone fabric, its performance in the field is not stellar. It does not appear to transfer moisture any faster than other polyurethane laminates. DriZone’s thick polyurethane coating does have the capacity to “bank” moisture as it is produced, up to a point, which will keep the interior of the tent dry for awhile.

A four-season tent should easily shed snow and ventilate well in wet conditions, but the Assailant is not designed well for snow. Pole sleeves on top of the tent hold the snow, and the shell does not have enough tautness and slope to shed snow, so it accumulates on the top of the tent and requires constant clearing to avoid overloading. All three vents are rather low and can easily be covered by snow, and there is no high vent except the door opening.

Furthermore, the tent does not manage moisture well. In dry weather it does just fine (like most tents do), but in wet weather moisture tends to stay inside creating heavy frost or condensation. The three vents have mesh in them which significantly restricts airflow, so it takes a pretty strong breeze to actually move air through the tent. The tent’s small stature exacerbates the condensation issue, i.e., the cold tent shell is close to the occupant, so condensation readily occurs and the occupant readily brushes against the wet walls.

The Assailant does not have a vestibule, so in wet weather wet gear must be brought inside the tent, which further exacerbates the moisture management issue in wet weather. Also, there is no overhang over the entry door to keep rain or snow from coming in, which would allow more effective use of the door for ventilation.

Im my opinion, a high-end breathable fabric single-wall tent should be shelled with a fabric that transfers moisture better than a polyurethane laminate. It should also have large weatherproof high vents to help exhaust moisture, and it should have a vestibule to stash wet gear. A PTFE or Epic shell would be better. Epic is lighter, but it also doesn’t transfer moisture very well at lower temperatures.

Finally, the Assailant at $319 is not a good value. For the same money and weight, you could have the Black Diamond Firstlight tent ($299), which provides 27.3 square feet of floor space and 42 inches of height, or the new Black Diamond HiLight ($339), which provides 27 square feet of floor space and is 40 inches high. Both tents pitch as tight as a drum, have steep walls that readily shed snow, and have an optional vestibule available. Closer in size to the Assailant is the Black Diamond OneShot tent ($290) which has 21.25 square feet of floor space, but is 36 inches high and will shed snow better than the Assailant. Admittedly the Black Diamond tents’ Epic fabric is only water-resistant and will wet through after about 5 hours of rain, and Epic is not very breathable in cold temperatures. Alternatively, one could spend a few extra bucks to get the Integral Designs MK1 Lite, which has a PTFE fabric shell similar to eVENT.

What’s Unique

Three-pole design for fast setup, convenient entry, small footprint, and useful interior space (except headroom) for one person.

Recommendations For Improvement

• Use a lightweight PTFE shell fabric
• Improve ventilation
• Redesign the roof so snow will slide off
• Add a vestibule

Introduction

The Rab Summit Extreme is based on the older Outdoor Designs Summit Extreme but with a few changes. It is also the only tent in the world market constructed of the amazingly breathable eVENT fabric. Unfortunately, the current Easton 7075 aluminum poles are heavier and less strong than the previous Easton Carbon FX models. The Summit Extreme also retains the Outdoor Designs model’s small footprint and low 28 inch roof, making it tight for two hikers. However, the low profile design, 13 guy-out points, and dual “donut link” tieout points make it the ultimate tent for extreme alpine placements and brutal weather conditions. This tent has few (if any) peers.

What’s Good

• The only tent currently made of eVENT fabric – amazing breathability and condensation resistance
• Current eVENT fabric is noticeably more breathable than the previous Exchange Lite Gore-Tex version
• Dual sealed tie out points can anchor climbers directly to the mountain while inside the tent
• Low ceiling, stiff poles, and 13 guy-out points create exceptional high wind stability
• Very tough and durable
• Aluminum Easton 7075 poles will bend rather than break like the previous Easton Carbon FX poles
• Weighs less than 4 pounds – very lightweight for a tent that handles such extreme conditions

What’s Not So Good

• Expensive in the U.S.- $450 but very expensive in the UK – £350
• Very cramped quarters and a very low ceiling make it a better solo tent and passable for a pair only for the most focused summit attempts
• A full 10 ounces heavier than the earlier Gore-Tex and Easton Carbon FX-poled Outdoor Designs version
• Previous Easton Carbon FX poles were lighter and stronger

Specifications

Tent	2006 Rab Summit Extreme (www.rab.uk.com)
Style	2 person single wall mountaineering tent
Fabrics	eVENT EV121: 112 g/ m2 weight with 40 denier nylon on the face. Breathability stats: MVTR using the Japanese B-2 method is 21997 grams over a 24 hour period
Poles and Stakes	Two Easton .340 in (8.64 mm) 7075 aluminum poles (ultimate tensile strength- poles- 96,000 psi, inserts- 96,000 psi), 16 aluminum V stakes 7 in (17.8 cm), seven standard adjustable guylines, seven elastic adjustable guylines
Dimensions	Length 82.7 in (210 cm), width 47.2 in (120 cm), height 33.7 in (85.5 cm)
Packed Size	17 in x 7 in x 7 in (43 x 18 x 18 cm)
Total Weight As supplied by manufacturer with all included items	Measured weight 4 lb 12.5 oz (2.17 g), manufacturer specification 4 lb 14.3 oz (2.22 kg)
Trail Weight Includes minimum number of items needed to erect the tent	Measured weight 3 lb 15.2 oz (1.79 kg); includes tent body, poles, six stakes, and two standard guylines
Protected Area	Total covered area 27.1 ft2 (2.52 m2), no vestibule
Floor Area/Trail Weight Ratio	6.86 ft2/lb based on 27.1 ft2 and weight of 3.95 lb
Protected Area/Trail Weight Ratio	6.86 ft2/lb based on floor + no vestibule area and weight of 3.95 lb
MSRP (	$450 (£350- UK Market)
Options	none

Performance

The Rab Summit Extreme tent is a new version of the nearly-identical Outdoor Designs Summit Extreme that we reviewed in 2005. Like the original, the Rab tent is truly focused: it is built for lightweight climbs in the most extreme alpine environments. It is extremely stable in high winds, is very breathable to keep condensation at bay (even when cooking inside the tent), weighs less than four pounds, and offers a unique system that allows you to tie off to an outside anchor without opening the tent to outside weather. While it is not the ultimate all-round tent, for alpinists pushing the envelope, the Summit Extreme may have no peer.

While the footprint of the Summit Extreme is almost the same as a Black Diamond/Bibler I-Tent or an Integral Designs MK1 Lite, the 28 inch height is much lower (42 inches on the I-Tent and MK1 Lite). This difference in height also lowers the angle of the walls. This results in a tent that is difficult to sit up in and reduces usable space due to steeply-sloped walls. I spent many nights in the Summit Extreme with two people; while this is certainly reasonable for a summit attempt, it is very cramped – especially with no available vestibule. Even a solo hiker over 6 feet needs to sleep at an angle to avoid contacting the steeply-angled walls. Sleeping at an angle, though, creates plenty of room for a solo hiker and gear. Usable space can also be greatly increased by using the guyouts on the sides and back.

The benefit of this low roof, though, is the tent’s amazing wind stability. The Summit Extreme is able to spill winds due to the low height and low-angled walls, and the short poles deflect less than longer ones in high gusts. The complement of 13 guyout points (7 at the mid-tent and 6 on the ground) equate to a tent that stands up to high winds better than any two-pole wedge “bomber” tent that we’ve ever tested. With the Rab Summit Extreme (and the Outdoor Designs version before), I found myself searching for the most exposed sites to find the limits of its wind stability. Despite many nights in open mountain-top pitches in the Cascades in the middle of the winter and several nights spent on Rainier during storms, I hardly approached the limits of this tent; a ridge on K2 might be a better test (and this is the first tent I would bring to that setting).

Because the doorway has such a shallow angle and there is no vestibule, rain or snow can pour in the Summit Extreme’s door when it is open. To combat this, the doorway can be unzipped at the bottom and you can sneak under the large overlapping flap. During a storm, this is the only way to keep the inside of the tent dry. Despite its obvious high alpine focus, a mesh door is included to keep insects out when camping at lower elevations.

Another downside of the low angles and side guy-outs (when in use) is a roof that is flatter than taller wedge tents. The Summit Extreme is very strong and stands up well to snow loading, but doesn’t shed snow as well as steeper-roofed tents (but it is much better than hoop tents such as the Hilleberg Akto). Occasionally banging on the walls easily keeps the roof clear during winter storms.

The two biggest changes with the new Rab Summit Extreme are the poles and the tent fabric:

Poles

The former Outdoor Designs Summit Extreme came with Easton Carbon FX poles while the current Rab version comes with more-standard Easton 7075 aluminum poles. According to Easton, the 0.340-inch aluminum poles have an ultimate tensile strength (PSI) of 96,000 while the Carbon FX are 200,000 – a full 208% stronger. Both pole sets share the same aluminum ferrules though, and those have a 96,000 PSI strength, making the weak point the same. When testing the Outdoor Designs tent, I accidentally fell on it, breaking one of the aluminum ferrules but leaving the carbon shaft intact. The bottom line is that the carbon poles used in the previous version are stronger, more rigid, and lighter. I feel the switch to Easton 7075 poles is a downgrade.

Tent Fabric

While the previous tent had walls constructed of Gore-Tex, Rab switched to eVENT fabric for the new Summit Extreme. As stated in our recent article “The eVENT Single Wall Tent: Here, Then Gone – What’s Replacing It?”, this tent is the only tent in the world currently constructed in eVENT, falling into the class of “bivy shelter” due to its low height. The use of eVENT is a serious bonus for the tent – it is amazingly breathable while remaining completely waterproof. While I was impressed with the previous Gore-Tex version, I was stunned by the breathability of this tent. In the field, I only experienced minimal condensation in the form of frost inside the tent and almost zero condensation in above-freezing conditions, including wet Cascade snowstorms.

At home, I tested the breathability by boiling water in the sealed tent for several 10-15 minute sessions. When finished, I collected condensation with a paper towel to weigh the total condensation. Each time, I was only able to detect moisture on the aluminum poles and on the seam tape – total condensation only measured 0.1 oz after a 15 minute boil. I simply could not make condensation occur in these conditions.

Given the right conditions, condensation will occur with any tent. However, I found condensaton extremely difficult to find under any conditions in the Summit Extreme. At the risk of exaggeration, I think eVENT is a magic fabric in a single wall tent, so it’s a shame it’s is only available on this one tent.

When you need extra ventilation, such as when cooking inside the tent, open the rear vent and crack the door open at the top – the doorway will still be protected by the flap. Hanging stove systems or lanterns hang lower than normal due to the low ceiling height. Move in the tent with care when using these systems (a partner melted a synthetic jacket when brushing past a lantern).

A unique feature of the Summit Extreme, shared by the older Outdoor Designs model, is the dual “donut link” sealed tie-in points. These points are created by hollow fabric loops that are sewn to the tent walls; one on top of the tent (hoop outside the tent) and one on the side (hoop inside the tent). To use these, you run a sling through the donut link on the inside of the tent and girth hitch the sling via the enclosed fabric hoop outside of the tent. Next you anchor the outside sling and tie into the inside sling. This system effectively removes the tent from the system WITHOUT having to pass a rope or runner through an opening in the tent (the entire tent could disintegrate and you’d still be safely anchored). This means that you can pitch the tent on a highly exposed ridge, on a big wall porta-ledge, or in an area of extreme wind with you and your partner secured directly to the mountain, upping security in extreme conditions dramatically. This feature makes the Summit Extreme the most secure tent on the market for really sketchy pitches.

At $450 in the U.S. and £350 in the U. K., the Rab Summit Extreme is a very expensive tent. However, it is a great value when compared with the Bibler I-tent ($540) and Integral Designs MK1L Lite ($600) and offers features such as eVENT fabric and tie-in points that those other tents don’t. The new Mountain Hardware Bunker ($450) is the only tent on the market that is made with a similar focus but it is a solo tent. For a party that needs these features and space for two climbers, the Rab Summit is an excellent value. For more casual mountaineers, however, a less narrowly-focused tent would be a better choice.

What’s Unique

The Rab Summit Extreme is a tent with a narrow focus – extreme alpine-style mountaineering – and it fills this niche without compromise. If you need the best tent with regard to low weight, wind stability, breathability, and anchoring options, this tent is your choice. You may have to accept compromises elsewhere (usable space, vestibule, expense) but if my life was on the line, this is the first tent I would choose.

Recommendations for Improvement

I would appreciate a higher ceiling on most occasions but that would compromise wind stability (and it would also eliminate Rab’s ability to use eVENT fabric). If you want a higher roof, go with another tent.

My only real gripe is the change from the stronger Easton Carbon FX poles to more-standard Easton 7075 aluminum poles. Rab may have made this change fearing that carbon poles are weaker than aluminum, but that is simply not the case; the Carbon FX poles are much stronger, more rigid, and are also lighter. In a tent this focused and expensive, the Easton Carbon FX poles are simply a better choice.