Welcome! Ultralight backpacking is my passion, and keeping up on new technologies, gear, and techniques relevant to UL backpacking is what floats my boat. I'm always looking for the lightest, most functional gear to improve a lightweight or ultralight backpacking kit, and report my impressions and field testing results here. For hikers wanting to keep up on the latest and greatest ultralight backpacking gear, this is a good place to hang out. Also, there is a lot of information here (and on our informational website Southwest Ultralight Backpacking) on useful techniques and backcountry etiquette -- food for thought for hikers wanting to lighten their load and their impacts.

My goal for Ultralight Insights is to understand, test, and report on new technologies and gear of interest to lightweight and ultralight backpackers. It's a passion after all, so we just plain enjoy talking about it. I hope readers will add their own wisdom and comments, respond to my questions, ask their own questions, and correct me if I get something wrong. Happy hiking! Will

Saturday, July 13, 2019

GEAR REVIEW: Topo Athletic Ultraventure Trail Shoe

By Will Rietveld

Topo Athletic is a relatively new shoe company that makes several trail models of interest to lightweight backpackers and trail runners. Features that appeal are light weight, synthetic materials, stitchless (welded) construction), a wide toebox, and snug heelcup. I have previously tested two Topo models – the Terraventure and Hydoventure – and loved both of them.

A new model in Topo lineup is the Ultraventure. This review will focus on how it’s a bit different from the two models I have previously tested, and how it compares with the popular Altra Lone Peak shoe, now in version 4. (Topo Athletic photo.)

Specifications and Features

Topo Athletic (www.topoathletic.com)
All synthetic: nylon mesh upper, EVA midsole, rubber outsole
Stack Height
30mm heel/25mm forefoot, 5mm heel to toe drop
Size men’s 12 tested: 11.9 oz/shoe; mfr specification 10.4 oz/shoe for men’s size 9; 8 oz/shoe for women’s size 7
Durable breathable mesh upper with TPU overlay pattern, 3-piece multi-density midsole, drainage gills for water release, Vibram XS Trek outsole, built-in attachments for Topo gaiter.


Most Topo shoe models have no or low heel to toe drop. The Terraventure and Hydroventure shoes I previously reviewed have 3 millimeters of drop; the Ultraventure has 5 a millimeter drop. Also, compared to those shoes, the Ultraventure has significantly more cushioning and support.

The upper is a soft nylon mesh with generous TPU overlays optimized for breathability and durability.

The outsole is Vibram XS Trek rubber with an aggressive lug pattern for traction and ample spacing between the lugs to shed mud and snow. (Topo Athletic photo.)

The Ultraventure has “gills” on both sides of the toebox to speed drainage and drying time.

Field Testing

I tested the Ultraventure in fall, winter, and spring in a wide range of conditions while day hiking, trail running, and backpacking; 33 trips in all. Because of the timing, my testing was mostly on trails, but I got in a good bit of off-trail use as well.

The first thing I noticed (and liked) about the Ultraventure is its extra cushioning. On long day hikes and backpacking days, I was able to hike 10 hours in them without foot fatigue, and I never had a blister.

A second feature I really like is their welded construction, meaning no stitched seams to come apart. And there is a very durable TPU rand around the toebox, a very vulnerable area for abrasion from off-trail bushwhacking.

Thirdly, I really like their wide toebox. That’s expecially important for me because I have wide feet (E width), but most thru-hikers and fastpackers like that feature because their feet swell during a long day on the trail.

Their stability on trails is excellent. However, when hiking off-trail (which is not necessarily this shoe’s intended purpose) I needed to tighten the laces tight over my instep to avoid rollover, especially crossing steep sidehills.

The breathability of the upper is very good. When a manufacturer chooses a fabric for the upper of a shoe, breathability needs to be balanced with keeping sand and dust out. I have tested shoes with a coarse mesh upper that were extremely breathable, but they allowed lots of trail dust and sand (when hiking in the desert) to go through, which is an obvious disadvantage. Topo has chosen well on the Ultraventrue.

Since the shoe is made with a breathable mesh, they are not water-resistant at all. They get wet inside easily, and I found they do not dry out quickly. I did not notice any benefit from the “gills” on both sides of the toebox. The gills function well to pump free water out of the shoes, but don’t seem to make much difference in removing absorbed water.

The Ultraventure has an aggressive traction outsole, which performs exceptionally well in dry and muddy conditions, but it tended to slip sideways on inclined snowbanks.

As you can see in the photo the Ultraventure came out of my testing with a lot of life left in it, which is a good testament to its durability.

However, I am not a fan of the Topo gaiter. It attaches with a typical lace hook at the front and two inverted “C” hooks at the heel. I found the lace hook comes loose sometimes, debris enters from the sides (which barely cover the shoe’s ankle cutout), and the rear hooks occasionally come loose. All of these issues occurred when I used the shoes for bushwhacking off-trail, which is not their intended use. The heel hooks are difficult to attach with the shoes on, so I typically leave the gaiters attached to the shoes and enter the shoe through the attached gaiter, which is a bit cumbersome but easily mastered. I prefer a tighter fit and a hook and loop attachment low on the heel.


I can say with confidence that the Ultraventure is my favorite Topo trail shoe so far. I really love the wide toebox, extra cushioning, extra support, traction, and durable materials and construction.

For runners and hikers who prefer a shoe with a wide toebox, the main choices are Topo Athletic and Altra shoes. Altra shoes are always zero drop, and Topo trail shoes have some heel rise (3mm or 5 mm). I have tested both brands in several models or versions and find that zero drop or low drop (for me) does not make any consequential difference. My feet readily adapt to the small differences in drop, and I don’t notice any difference in performance; both brands perform well for my purpose.

I like the lighter weight of the Topo shoes compared to the Altra Lone Peak, which is a beefier shoe, and I also like the Topo welded construction compared to the Altra stitched construction.

Toebox width of the Topo Ultraventure (left) compared to the Altra Lone Peak 4 (right). I overlaid the toebox of the Ultraventure with the Altra Lone Peak 4 and found the outside width to be nearly identical (the Topo shoe was about 2 millimeters wider), so no significant difference. Note that the inside width is not easily measured.

I am not impressed with the “mesh” upper of the Altra Lone Peak 4; it’s a bit stiff and doesn’t seem to be very breathable. I like the upper on version 3.5 more. I much prefer the upper on the Ultraventure, meaning the combination of soft breathable mesh, TPU overlays in the right places, and welded construction.

However, I will take the Altra Trail Gaiter any day compared to the Topo Gaiter. It stays attached and keeps debris out. I have not tried the Altra Four-Point Gaiter.

Which shoe do I like better? Well, it’s like loving your children; you love each one for different reasons, and they’re both exceptional. Both deserve a close look by trail runners and lightweight backpackers.

Saturday, May 11, 2019

GEAR REVIEW: Montbell Tachyon Parka (Windshirt)

By Will Rietveld

Just to be clear, although this jacket is called a “Parka”, it is in fact a hooded, featured windshirt. At 2.5 ounces, it’s likely the lightest one to be found. Montbell’s Ex Light Wind Jacket, made of the same fabric but Spartan for features, weighs 1.7 ounces. So, are the Parka's features worth the extra 0.8 ounce?

The Montbell Tachyon Parka features a full-height front zipper, an attached adjustable hood, two zippered hand pockets, and an internal key pocket. It’s made of a more breathable version of their 7-denier Ballistic Airlight nylon fabric.

Specifications and Features

Montbell (www.montbell.us.com/)
Tachyon Parka
7-denier Ballistic Airlight ripstop nylon with Polkatex DWR
Attached adjustable hood, 2 zippered hand pockets, full-height front zipper, interior key pocket, elastic cuffs
Size Large tested, 2.7 oz; manufacturer specified weight (size Medium) 2.5 oz


Montbell is known for providing a range of versions within each of its product categories, so it is not surprising to find 13 different windshirts on their website, including a wind vest! The Tachyon series is the lightest, featuring 7-denier fabric that is remarkably water-resistant and durable.

According to the Montbell website, the “Tachyon Parka has been redesigned to significantly increase breathability without sacrificing its wind blocking performance. With the new fabric, we have manipulated the weave and how we process the material to expertly balance its ability to release built up humidity inside the jacket, yet still block wind.” Improvements are always welcome, but how much difference does it make?

The Tachyon Parka has the “essential” features most hikers would want – a full-height zipper, attached adjustable hood, and zippered hand pockets. It’s actually pretty amazing that Montbell is able to produce a windshirt with these features that weighs just 2.5 ounces (size men’s Medium).

Field Testing and Performance

I tested the Tachyon Parka on 23 outings while day hiking, backpacking, snow walking, snowshoeing, and mountain biking. I normally wear a size Large, and the sizing is spot on. I'm wearing it layered over an ultralight down jacket, camped at 11,800 feet on a chilly late September morning.

 I have previously tested the 1.6 ounce Montbell Tachyon Jacket (now the Ex Light Wind Jacket), which is Spartan, save for a full-height front zipper. I really like it for its simplicity and light weight, and it’s a no-brainer to take a windshirt in addition to a rain jacket for windwear because it performs better for that purpose.

Now I have to evaluate carrying the Tachyon Parka instead, and adding 0.8 ounce to my gear kit. It’s weight creep; so is it worth it?

The hood adds a little extra warmth on a cold morning, and its nice to have when the wind is howling in my ears. I often wear a billed cap over the hood while hiking to keep the hood from inflating in the wind.

I also sleep in a hoodless sleeping bag these days, and having a hood on a windshirt or down jacket is a good way to keep my head warm as needed.

And the zippered pockets are handy for carrying, and securing, smaller items on the trail and in camp.

Montbell claims that this new Tachyon windshirt has increased breathability because of changes in the manufacturing of their 7-denier fabric. So, is there a noticeable difference? I would say yes, there is, but it’s not dramatic. In cold conditions I can hike for extended periods without steaming up. In cool shady conditions I can hike longer before getting too hot. However, in the Southwestern US where I live, the sun is the wildcard. Even on cooler days, if the sun is shining, it doesn’t take long to overheat while hiking while wearing a windshirt. As usual, hiking while wearing a windshirt is most comfortable when it’s cloudy, cool, and breezy/windy.

When you think about it, a breathable windshirt may be an oxymoron, or at least a fine line to achieve. Like a waterproof-breathable rain jacket -- which needs to be waterproof first, then breathable – a windshirt needs to be windproof, then breathable. In each case the latter factor is a measured amount that does not compromise the former factor. And so the bottom line is a W-B rain jacket is not very breathable, and a breathable windshirt is not very breathable either. But the relatively small amount of breathability helps, and is better than a solid barrier.


It gets down to whether you have a use for the features or not. The extra weight is miniscule to a lightweight backpacker, but it matters to an ultralight backpacker trying to keep her base weight down to 5 pounds or so.

Since I started using a hoodless sleeping bag, a hooded windshirt and a hooded down jacket have more utility to keep my head warm, so I’m more likely to carry a hooded windshirt.

It’s nice to have options.

Friday, May 10, 2019

GEAR REVIEW: Altra Lone Peak 4 Mid RSM and Low Trail Shoes

By Will Rietveld

The new Altra Lone Peak 4 takes another step in the evolution of this popular trail shoe. It’s popular because its shape/fit, materials, support, cushioning, traction, and light weight are on target with what hikers and trail runners want.

What’s new with this new edition, and how is it better? And further, are there advantages (or not) of switching to the mid-height waterproof/breathable version versus a traditional low-cut shoe?

I started out testing the new Altra 4 RSM Mid (left), but after discovering a few quirks I decided to compare it with the Altra 4 Low (right). This review is the outcome of one hiker’s experience with both versions.

Specifications and Features

Altra Running (www.altrarunning.com/)
Lone Peak 4 Mid RSM and Low
All synthetic. The Mid RSM has an eVent waterproof-breathable membrane; both shoes have a nylon fabric upper with TPU overlays, EVA midsole, and rubber outsole.
Stack height 25mm, zero drop
Notable changes are: eVent membrane in the waterproof-breathable version, new nylon fabric upper; an added webbing loop on the instep that enables better cinching ability; a new full-length rock plate that resembles the skeletal structure of the foot; and an improved traction outsole.
Size 12 tested. Average weight of the Mid RSM is 15.2 oz; average weight of the Low is 12.3 oz.
Mid RSM is $160; Low is $120


RSM stands for Rain, Snow, and Mud. The big change in the Mid is a switch from NeoShell to eVent for the waterproof-breathable membrane. I have always preferred eVent because of its better breathability. Both the Mid and the Low are available with a mesh upper that is not waterproof, and the RSM waterproof-breathable version.

This is my first time testing the mid-height version of the Lone Peak, so I have no experience with the previous NeoShell version to compare it to. However, I have tested the Lone Peak 3.0 and 3.5 Low.

The most noticeable change from the Lone Peak 3.5 is the new upper fabric, which looks like ripstop nylon compared to the woven fabric look of its predecessor. Both have a soft feel. The 3.5 had a dense overstitching pattern on the toebox to reinforce it, while the 4.0 has TPU overlays.

The other main upgrades – a static loop on the instep to enable better clinching, enlarged and articulated rock plate, and improved traction outsole – are less noticeable but significant and functional.

Overall, the improvements justify kicking up the Lone Peak up a notch from 3.5 to 4.0.

Field Testing and Performance

I tested the Lone Peak 4.0 on a total of 33 outings, which included trail hiking, off-trail hiking, trail running, snow and slush hiking, backpacking, scrambling, and mountain biking.

Unfortunately, on only my second time out in the Lone Peak 4 Mid RSM I caught the toebox of one shoe on a tree stub and tore a hole in the upper mesh. I tried repairing it with a Type A patch and McNett Tenaceous Tape, but neither product worked. So that shoe leaked through most of my testing.

In my testing of the Mid RSM in slush and water, I ended up with damp socks on both feet; the left one more so because of the patched tear. Upon further inspection I noticed that the right shoe also had some small abrasion holes in the fabric on the sides of the toebox. This would indicate that the new fabric is not all that durable, at least for off-trail backpacking.

 Weight-wise, in my shoe size, the Lone Peak 4 Low is only a smidgeon heavier than the version 3.5 (12.3 oz/shoe versus 12.2 oz/shoe). The MSRP has remained the same ($120).

My rationale for testing the Lone Peak Mid 4 RSM was my perception that it would provide better ankle support and be more stable and protective for off-trail backpacking. Also, the waterproof-breathable version would be a good choice for hiking in early- and late-season snow, as well as summer rains.

However, overall, the Mid 4 RSM did not meet my expectations.

Before I get into the details, allow me to mention that your experience may be different; choosing a shoe brand and model is a very personal thing, like choosing what type and brand of underwear you wear. You eventually determine what works for you.

In my case, I have wide feet (EE width), high arches, and a high instep. I’m attracted to the wide toebox and snug heelcup of the Altra’s, but even with that I need to wear thin socks in them to avoid them being too tight. For hiking, I want an all-synthetic, supportive, cushioned, high traction shoe.

Back to my experience with the Lone Peak Mid 4 RSM. First, the tear in the upper was totally a mishap, and I don’t feel that the new fabric is any less durable than previous versions. But it is still vulnerable to abrasion on the sides of the toebox.

My main issue is its funky fit (for me), which resulted in a constant flip-flop sound while hiking in them. I tried tightening them down as much as I could, switching to thicker insoles, and wearing thicker socks, but nothing worked. It was mostly an annoyance and did not result in blisters or anything like that. Finally, I did not notice any improved support or protection from the Mid version.

When I got the Low Mesh version midway in my testing, I immediately noticed that they were a better fit, provided more agility while hiking, and were simply more comfortable. I could also notice the Low version’s lighter weight; 3 ounces less per shoe.

After noticing a significant difference in the comfort and performance of the two versions of the Lone Peak 4, I dived into comparing details of the two shoes to try to account for the perceived differences. Notable differences in the Mid are taller shoe height (obviously), the lacing system at the top of the shoe, thicker laces, thicker padding around the ankle, a looser fit around the ankle, and an added exterior thick TPU band around the heel. 

So, the devil is in the details, so to speak – the Mid is a different animal compared to the Low. It’s not just the Low shoe with a little height added; it’s a different shoe.

I also dived into trying to figure out what was causing the flip-flopping effect. I thought it might be heel rise due to a looser heel cup, but when I measured the heel cup width of the two shoes the difference was negligible.

I conclude that the flip-flopping of the Mid version is due to the multiple design differences between the two shoes, which overall do not provide an enveloping fit like the Low.

The other upgrades in the new Lone Peak 4 are all good improvements. The static lacing loop over the instep does provide better cinching, which makes this trail running shoe much more stable while hiking across steep sidehills. Also the improved rock plate and traction outsole are distinct improvements.

Here’s the Lone Peak 4 Mid RSM and Low side by side, both in size men’s 12.

Here’s how the Lone Peak Low 4 (green) compares to the Lone Peak 3.5 (red). Both are the fabric (non-waterproof) version. The new version has a more aggressive outsole, although the old version is pretty worn down.


The outcome of my testing was a bit different from what I expected. For me, the funky fit, flip-flopping, and lack of improved support made the Lone Peak 4 Mid RSM a disappointment. When the traditional Low Mesh shoe arrived, my feet told me “I like these much better!”. Granted, they get wet easily, so they are not suited for hiking in snow and slush, but they are just fine for summer hiking where getting them wet is less of an issue because they dry out quickly.

I will continue to be a fan of the Altra Lone Peak because of their wide toebox, support, and comfort. However, my experience with the Mid version reinforced my preference for a low-cut shoe; I simply prefer the lighter weight, improved agility, good traction, and adequate support they provide. In this case a taller shoe didn’t offer any more.

Monday, January 28, 2019

GEAR REVIEW: Gossamer Gear Lonestar 30 Day Pack

By Will Rietveld

The new Lonestar 30 by Gossamer Gear is a multi-purpose day pack for trail, rock, or snow. Its 30-liter volume and internal frame make it especially useful for cool and cold weather activities, snow sports, or climbing, where extra volume and support are needed to carry essentials. It’s also a good choice if you are the family Sherpa. At 29.5 ounces, it’s not ultralight, but that doesn’t matter so much for day trips; what’s more important are fit, carry comfort, and utility. So, how does the Lonestar 30 stack up in that perspective? (Hint:  it’s my new favorite day pack, and I explain why in this review.)

The Gossamer Gear Lonestar 30 Day Pack is an internal frame top loader with loads of features. 

 Specifications and Features

Gossamer Gear (www.gossamergear.com)
Lonestar 30 Day Pack
30 liters
Measured weight 29.3 oz; manufacturer specification 29.5 oz
Pack body is 100-denier Robic ripstop nylon, bottom and reinforcements are 200-denier Robic nylon; side pockets, hipbelt pockets, and shoulder strap sleeves are nylon mesh
Removable internal contoured aluminum tubular frame, removable hipbelt with 2 zippered pockets, attached fitted top lid with full-width zipper and key clip inside, 3-inch wide shoulder straps with mesh sleeves, hydration sleeve behind backpanel + 2 hose loops, 2 mesh side pockets, internal zippered security pocket, drawcord closure, 2 tool loops and 2 daisy chains on pack front, 2 extended straps with buckles on daisy chains, zig-zag side compression, additional tiedown loops on top lid and bottom of pack


The following photo gallery shows the pack’s design and features.

Front View – The Lonestar has a fitted top cap secured with one buckle. There are two daisy chains on the front, each with a tool loop at the top and an attachment strap at the bottom.

Side View – Each side has a zig-zag compression strap that can be released and connected to the opposite side to attach gear to the front of the pack.

Backpanel – The shoulder straps are 3 inches wide and nicely padded, and the backpanel has good padding for the shoulders and lumbar region.

Top View – The top pocket has a full-width zipper on the shoulder strap side and four attachment points on top.

Frame – The tubular aluminum frame is contoured to fit the user's back, and weighs just 3.5 ounces.

Side Pockets – are made of stretch nylon mesh and large enough to fit a 1-liter water bottle.

Hipbelt Pockets – are large enough to carry a cell phone, camera, or numerous smaller items. 

Security Pocket – The internal security pocket is the full width of the pack and zippered for easy access.

Hydration Sleeve – A full-height compartment behind the backpanel is the hydration sleeve. It will easily hold a 3-litter reservoir. The closure is a toggle and loop.


I tested the Lonestar 30 for a three-month period (November-January) doing cold weather and snow-related activities – day hiking, snow hiking, snowshoeing, cross-country skiing, and backcountry skiing, for a total of 15 trips. I normally carried 6 to 10 pounds but on a few occasions I loaded the pack to 15 pounds to test its comfort (photo by John Martin).

Features – Full-featured may be an understatement, considering the list in the table. Features mean weight, that list of features adds up to a pack weight of 29.3 ounces (measured weight), so the Lonestar 30 is not ultralight. However, pack weight doesn’t matter so much on a day pack, and features are more appreciated. Actually, carrying a bit of weight on day trips is good training for backpacking.

My favorite features on the Lonestar, besides the internal frame, are the shoulder strap mesh sleeves, hydration sleeve behind the backpanel (which provides more room in the main compartment), and the internal security pocket.

Fit – The Lonestar comes in one size which is claimed to fit torsos from 16 to 24 inches (generally, persons from 5’-4” to 6’-4”) and waists 28 to 48 inches. The measured pack torso length is 18.5 inches (underside of shoulder strap to center of the hipbelt attachment), which translates to a size Medium. That said, the pack fits me (6-feet, 20-inch torso) quite well, with the top of the shoulder straps about 1-inch below my shoulders. Taller hikers will have more wrap-around the shoulders, and shorter hikers will have a gap above the shoulders.

I personally like a framed day pack because it simply fits better and carries better. The pack is more rigid and keeps its shape when worn. What is especially nice about the Lonestar is Gossamer Gear’s contoured tubular frame is very lightweight (3.5 ounces) fits the shape of your back, and is easily adjusted for a custom fit. A frameless day pack may have a curve in the backpanel when you use the hipbelt (if the pack has one), and will hang straight if you do not use the hipbelt.

That said, the Lonestar fit me very well and carried very well with different loads. For cool and cold weather trips, the 30-liter volume is about right. However (for me) it has too much volume for most warm weather trips; about 20 liters is better, and my pack of choice is the Gossamer Gear Type 2.

Weight Carrying Capacity – The Lonestar’s internal frame ups the load limits and carrying comfort quite a bit. The frame is a version of the contoured aluminum frame Gossamer Gear uses in their backpacks. They suggest a maximum load of 25 pounds and comfortable load of 20 pounds for the Lonestar 30. Loads that heavy might happen if you use the pack for climbing, or a full load of gear for backcountry skiing, or attach snowshoes to the front of the pack. Note that the pack does not have ski loops for carrying skis.

Versatility – The Lonestar 30 is designed to be versatile, and I found that to be the case. I carried the Lonestar for a variety of activities, all in cold weather where more clothing and extra equipment (like a shovel, avalanche probe, insulated bottle, ski skins, ski waxes, etc) are carried. The Lonestar carried it easily and I hardly noticed the weight or volume.

Backcountry skiing along a (mostly) frozen stream. The day started with single digit F temperatures and warmed to above freezing. That requires a lot of clothing adjustments, and a larger pack to carry clothing and gear (photo by Travis Ward).


Gossamer Gear hits the mark on several fronts. The Lonestar 30 is full-featured, versatile, and durable. For a larger volume day pack, the Lonestar 30 combines on-target design and dimensions, a long list of useful features, and a form-fitting frame. It all comes together perfectly. This is now my go-to pack for cold weather activities, especially snow sports.

Although the pack carries wonderfully, I would not use it for backpacking because of its weight. All those features are nice to have for a day pack, but add too much weight for a backpack.

Tuesday, January 22, 2019

GEAR REVIEW: Patagonia Capilene Air Baselayers

By Will Rietveld

The new Patagonia Capilene Air baselayers (top and bottom) are their warmest. They remind me of the old fishnet underwear that was warm and breathable by trapping a lot of air between it and an overlayer. But the comparison ends there. The Capilene Air baselayers are more high-tech than was ever imagined at the time of the fishnet underwear. They are made of an air blasted 51% Merino wool and 49% recycled polyester yarn, and utilize a new knitting technology that creates a 3-dimensional garment that is nearly seamless. They are noticeably lightweight compared to other garments providing the same warmth. And I found them to be very versatile. Read on for the details.

The Patagonia Capilene Air baselayers Top and Bottom are knitted from a yarn consisting of 51% Merino wool and 49% recycled polyester and have very few seams.

 Specifications and Features

Patagonia (www.patagonia.com)
Capilene Air Crew Top and Bottom (a hooded Top is available)
Measured weight size men’s Large: Top 7.3 oz, Bottom 6.9 oz; manufacturer specification (size Medium): Top 5.2 oz, Bottom 5.9 oz
5.6-oz (190-g) 51% merino wool/49% recycled polyester seamless box-stitch knit comprised of 18.5-micron-gauge lofted wool
3D fabric is soft against the skin, very stretchy, and brushed + nearly seamless to eliminate chafing
$129 each


The thing that impresses me most about the Capilene Air baselayers is how S-T-R-E-A-T-C-H-Y they are. Their 3D knit allows them to stretch way out to be worn over something else, and then contract right back to a trim-fitting baselayer. They don’t stretch out and remain baggy.

Close-up of the Capilene Air knitted fabric.

I followed Patagonia’s size charts and found that I would take a size Large in both garments, so that’s what I tested. I’m 6 feet tall and 165 pounds. When the baselayers arrived, both fit loose and seemed to be one size too large. It turned out that this was fortuitous, which I will explain shortly.

The size you choose depends somewhat on how you intend to use them. If you want to use them only as a baselayer – with a body-hugging fit – go one size smaller than the Patagonia size chart. If you want them to be versatile – so they can be worn as a baselayer, midlayer, or outerlayer – go with the Patagonia size chart. It will fit a little loose, but acceptable, as a baselayer.


I tested the Patagonia Capilene Air baselayers on a total of 46 outings including car camping, backpacking, day hiking, snow walking, cross-country skiing, backcountry skiing, snowshoeing, snow shoveling, igloo building, and volunteering on a Christmas Tree lot. This photo shows the Capilene Air Top worn as a midlayer, and the Bottom worn as an outerlayer in camp.

I tested both the Top and Bottom as a baselayer, midlayer, and outer layer. That’s the versatility I mentioned earlier – opting for a looser-fitting size allowed me to wear the baselayers any way I desired.

For example, I frequently donned the Top over my hiking shirt, like a fleece pullover, when I need a little more warmth. In camp, for more warmth, I wore the Top as a midlayer over my hiking shirt and then donned an ultralight down jacket and a windshirt or UL rain jacket over the underlayers to seal in the heat.

The Capilene Air Top worn as an outerlayer on the trail in early morning cold temps.

The bottom is a little less versatile because I rarely hiked in it. I mainly wore it as a baselayer or midlayer in camp. Again, it was very convenient to simply put it on over my hiking pants or shorts. It would be very warm for more sedentary situations, like ice fishing, car camping, or cabin wear.

I found it best to simply think of the Capilene Air garments as layering garments, and use them accordingly to regulate temperature. I did not wear them as baselayers on the trail, unless the Top was the only layer I wore, or I wore it under a windshirt in cool temperatures. When the Top is covered by one or more midlayers it is too cumbersome to take it off when I get overheated. Temperatures needed to be in the single digits F, or lower, to comfortably wear them as baselayers while hiking, snowshoeing, or skiing.

For hiking or cross-country skiing on cool winter days in the 20s F, the Top as a single layer under a windshirt is sufficient. When temperatures are in the teens F, the Top as a baselayer or midlayer under a windshirt is sufficient. For snowshoeing and skiing, especially if its windy, I add a hardshell to stay dry if I crash (snow sticks to the fabric like it does to fleece).

The Capilene Air Top worn as a baselayer under a heavier weight merino wool shirt while snowshoeing. The combination was comfortable in early morning colder temperatures and on the descent, but I overheated on a 1000-foot steady climb.

I also found the Capilene Air to be very breathable, but again it’s important to wear it as part of a layering system and use it accordingly. For example, wearing the top alone hiking when the temperature is in the 30s F can be very comfortable, even with a light breeze, but it gets chilly if the wind picks up, so time to don a windshirt and it’s comfortable again using the front zipper to regulate temperature.

Since the Capilene Air layers are knitted, one would suspect that they would snag easily. But I did not find that to be the case. I often wore the top as a single layer for hiking when temperatures are above freezing, and bushwhacked through brush on many occasions without damage. However, I did find two drawbacks: 1) the fabric pills somewhat on the underarms from wearing it as an outerlayer, and 2) debris and lint of all kinds readily stick to the fabric, and also Velcro.

After many wearings, the underside of the sleeves are pilled somewhat.


The Capilene Air baselayers are lighter than a typical wool baselayer and (in my opinion) provide a lot more warmth and versatility. But the Capilene Air (especially the Top) goes beyond a baselayer. It’s best to think of it as part of a layering system where it can function as a baselayer, midlayer, or outerlayer depending on the conditions, activity, and convenience. If it’s worn simply as a baselayer for active pursuits, you are very likely to overheat. For more sedentary situations it provides loads of warmth.

Wednesday, September 26, 2018

GEAR REVIEW: Zpacks Classic Sleeping Bag and Goose Down Hood

The Zpacks Classic Sleeping Bag delivers on all fronts; they have a size to fit most everyone, its lighter weight for its temperature rating compared to other manufacturers’ bags, its highly versatile to use, and it’s a great value.

By Will Rietveld

Over about 18 years as an outdoor writer and gear tester, I have reviewed a lot of sleeping bags, and find that an ultralight sleeping bag is one of the more difficult gear selections. The challenge is to get enough warmth and inside room, while minimizing weight.

I have certainly found out what doesn’t work: many ultralight bags are way overrated, so they are not warm enough; many bags are too darn tight, so there’s no room to wear insulated clothing inside, and warmer versions are too heavy.

I finally found the Zpacks Classic Sleeping Bag, which has been around for awhile, but it took me awhile to appreciate it. This review is basically a testimonial of my evolutionary experience with ultralight sleeping bags, and how I arrived at, and love, the Zpacks Classic Sleeping Bag.

The hoodless Zpacks Classic Sleeping Bag has the zipper on the bottom side. Its available in 24 different combinations of temperature rating, length, and girth. (Zpacks photo)

Specifications and Features

Zpacks www.zpacks.com
Classic Sleeping Bag
Shell and lining are 0.59 oz/sq yd Ventum ripstop nylon with DWR, insulation is 900 fill-power white European Goose down, ¾ length YKK #3 double-pull one-way zipper
Temperature/Girth/Length Options
3 temperature options (35F, 20F, 5F) x 3 girth options (slim, standard, broad) x 4 length options (short, medium, long, X-long). The broad girth is available only in long and extra long lengths.
5F, Standard width, Long length tested. Mfr. specified weight 24.8 oz, measured weight 24.3 oz.
Smaller vertical baffles on upper part of bag prevents  down from shifting to sides, 30% overfill in chambers to allow for down compression over time, horizontal baffles in footbox area, black lining for quicker drying, zipper on the bottomside of the bag, flat clip at top of zipper keeps zipper from opening, elastic cord closure around the neck. No zipper baffle or neck baffle, hoodless.
Goose Down Hood
850 fill-power down, same shell fabric, 1.3 ounces (1.55 measured), $65


The Zpacks Classic Sleeping Bag is unconventional compared to a traditional mummy bag. It’s a minimalist bag that substitutes versatility and functionality for weighty features.

The bag does not have a hood. A ¾-length zipper is located on the bottom of the bag, so it doesn’t need a zipper baffle. There is no neck baffle inside the bag; rather a thin drawcord draws the top of the bag snug around your neck.

The bag is designed to be used as a quilt on warmer nights (above) or as a sleeping bag (previous photo) on colder nights. (Zpacks photo)

A light hat is needed on warmer nights, and warmer headwear like the Zpacks Goose Down Hood is needed on colder nights.

By the numbers, the Classic Sleeping Bag has a lot of warmth for its weight. It’s 0.59 ounce per square yard Ventum ripstop  nylon shell and lining is the lightest woven fabric I have encountered to date. For the size tested, the shell, zipper, and drawcord account for only 26% of bag weight, the remaining 18.2 ounces (74%) is 900 fill-power down.

While other sleeping bag manufacturers limit the number of temperature and size options, Zpacks does the exact opposite. The Classic Sleeping Bag is available in a total of 24 temperature, girth, and length options. That’s amazing!

To get in/out of the bag, one can turn the zipper to one side to open/close it, then shift the zipper to the bottom; or simply enter the bag from the top. 

The head end of the bag has a thin elastic drawcord to snug it around your neck. A flat clip at the top of the zipper keeps it from opening on its own. (Zpacks photo)

Ventilation options (from warm to cool air temperatures) are: open the bag and use it as a blanket; sleep with the partially open zipper on top, drawcord open; sleep with the zipper closed on top, drawcord open; and sleep with the zipper on the bottom and drawcord drawn up around the neck. Headwear would range from none to the Zpacks Goose Down Hood.

The Zpacks Down Hood (made by Goosefeet) is insulated with 850 fill-power down and uses the same shell fabric as the Zpacks Classic Sleeping Bag. It's anatomically designed to cover the head and has a dropped tail on the front and rear to tuck into a jacket. A thin drawcord on the front draws it up around the face; it will cover your eyes while sleeping if you want. Weight is 1.3 ounces and MSRP is $65.

Sleeping Bag Conundrums

There are lots of ways to go wrong when choosing an ultralight sleeping bag, and most manufacturers don’t help much in providing more choices or selection assistance.

Typical ultralight sleeping bags from mainstream manufacturers tend to be overrated for warmth (despite the EN standard), they’re available in only a few sizes (typically Regular and Long), are too tight in shoulder girth (often 58-59 inches), and expensive.

Ultralight backpackers tend to choose a lighter bag and wear camp clothing inside to extend its warmth. Then the issue becomes finding a bag with enough shoulder girth to accommodate that. There are few bags available in Regular length that have enough shoulder girth, I prefer 61 inches or more, but many bags are only 58 or 59 inches. I’m fairly thin and I find it very difficult to zip into a bag with 59 inches of shoulder girth. So I often resort to getting a size Long to get the girth I need, but I get unneeded length along with it.

It’s not a bad idea to opt for a warmer bag to avoid getting cold, and to compensate for manufacturers’ optimistic temperature ratings. A bag rated at 20F with at least 61 inches of shoulder girth is a good choice for many backpackers, however body size and individual thermal needs vary a lot.

Additionally, there are individual preferences for a full-length zipper (or not), attached hood (or not), or the simplicity and freedom of a quilt.

Through trial and error, my personal preference is for a quilt when temperatures are warmer (above 35F), and a mummy bag when it’s colder. A mummy bag is simply more thermally efficient – it holds heat inside better. However, it’s hard to find a mummy bag that’s warm enough, roomy enough, and light weight (all 3). That’s the conundrum.

Then I discovered, through friends that have them, the Zpacks Classic Sleeping Bag. The beauty is you get to choose your desired temperature rating, shoulder girth, and length – and Zpacks provides simple guidance on how to choose. Additionally the bags are very light weight and reasonably priced.

A 20F rated bag would normally be sufficient for me, if I wear camp clothing inside the bag on colder nights. However, I chose the 5F bag for three reasons: (1) I’m getting older and don’t have much body fat, so I get cold easier; (2) the 5F Standard girth/Long length bag weighs just 24.8 ounces, which is about the same as a 20F bag from other manufacturers; and (3) I wanted a warm bag to extend my backpacking into the shoulder seasons. Zpacks specifies that this bag has 18.2 ounces of down fill, which is good assurance that the bag will be warm.

This all sounds good; so how did it work out? Read on for my testing report and evaluation.

Field Testing

I tested the Zpacks Classic Sleeping bag on 5 backpacking trips and one road trip in late summer and fall in Central and Southwestern Colorado. I usually camp on the alpine tundra above 12,000 feet, where it often drops down to freezing at night. This photo was taken in late September, when the tundra is colorful and nighttime temperatures are dropping into the low 20s. The shelter is the Zpacks Duplex Tarp.

I followed Zpack’s online advice to choose my bag size. I’m 6 feet tall, so I went with size Long. To determine bag girth needed, Zpacks recommends measuring the girth around my chest and arms (46 inches), adding 8 inches for wiggle room, and adding a little more if I want extra wiggle room. So, 46 inches plus 8 inches plus an extra 5 inches adds up to 61 inches, which is their Standard girth bag and my desired girth.

The Zpacks sizing guide worked well for me; the bag I tested is a good match in length and girth. I’m 6 feet tall and the size Long bag is a good fit for length. The 61-inch shoulder girth allows sufficient room to wear a lightweight down jacket inside the bag if needed. So far I have only needed to wear a baselayer plus an ultralight down jacket. From my previous years of mummy bag testing, I have found that I need at least 61 inches of shoulder girth, so the Zpacks sizing guide is spot on.

During my testing I typically camp in the alpine zone at elevations of 12,000 or more, so summertime nighttime lows can drop to freezing. By late summer and early fall I had encountered low temperatures down to freezing (3 nights) and below freezing (27F, 24F, and 14F) three nights.

I comfortably used the bag as a quilt in nighttime temperatures down to about 35F, and really like the quilt option when temperatures permit. At about that temperature (which I call the 4 o’clock freeze) I start feeling cold spots where the quilt is not adequately tucked in. Then I zip up the bag and switch to sleeping bag mode. On the coldest nights I donned the Zpacks Down Hood and tightened the drawcord to snug the bag around my neck, and slept warm as toast the rest of the night.

On my coldest night, in late September camped on the alpine tundra at 12, 500 feet, I wore several layers of camp clothing inside the bag and stayed comfortably warm. The bag has sufficient girth to accommodate the extra bulk. My water flask and rehydrating breakfast were frozen solid.

I personally like a hoodless sleeping bag. With the accessory down hood the system is equivalent to a mummy bag. The advantage is I turn over inside the Zpacks bag, rather than turning a conventional mummy bag with me so the hood is in the right direction.

I also have no issues with entering a sleeping bag from the top; it’s simply not that difficult to slide in. If that is not an option for you, it is easy to shift the zipper to one side or the other and enter/exit using the zipper. It doesn’t have a zipper baffle, so snagging is not an issue.

As with any down sleeping bag, it’s a good idea to hold the bag up against the sky to check the down distribution. The down will shift to some degree in most bags, so it’s important to check for areas where the down is sparse, and shake the bag accordingly to more evenly distribute the down. So far, the Zpacks bag has performed well in this regard.

Warmth-wise, the 5F-rated Zpacks Classic Sleeping Bag has been reliably warm so far, which is really nice; no more chilly nights in a 30F bag. I expect it to be warm into the single digits if I wear down booties, lightweight down pants, and a down jacket inside, along with the Zpacks Down Hood. Those are items I normally take for campwear for shoulder season camping at high elevations.

 This photo shows how much the bag lofts up. For comparison, the sleeping pad is 2.5 inches thick. I measured the double layer loft at 8 inches, which is a lot. According to the Backpacking Light table of sleeping bag loft versus temperature rating, this comes out to a -20F rating (!)


Some hikers may see the Zpacks Classic Sleeping Bag as unconventional, and it is, but it is one that should receive serious consideration by anyone looking for an ultralight sleeping bag. With 24 temperature, length, and girth options, there should be a good fit for most any body. Ultralight bags from many other manufacturers are simply too tight, with shoulder girths of only 58-59 inches. Also, a good way for a short person to save weight is to get a size Short bag, and Zpacks has one that will fit your dimensions.

The bag is also the most versatile I have tested. It can be used as a quilt in warmer temperatures, with the zipper partially open or on the topside in chilly temperatures, and as a mummy bag equivalent (using a down hood) when it’s cold.

The Zpacks bag also provides the most warmth-for-the-weight I have encountered. The shell, zipper, and drawcord weigh only 6.6 ounces for the bag I tested, the remaining 18.2 ounces is 900 fill-power down. I was able to get a 5F rated bag for the same weight as most manufacturers’ 20F rated bag, and some 30F rated bags.

Finally, the Zpacks Classic Sleeping Bag is an excellent value. Most manufacturers’ 20F and 30F ultralight bags are priced in the $400 to $500 range; the 5F bag tested is $399, and a 20F version is $379.

Overall, the Zpacks Classic Sleeping Bag delivers on all fronts; they have a size to fit most everyone, its lighter weight for its temperature rating compared to other manufacturer’s bags, its highly versatile to use, and it’s a great value.

Likewise the Zpacks Down Hood is the lightest to be found at 1.3 ounces, and it is well fitted and very warm.