The hoodless Montane Slipstream GL Jacket is made of the new Pertex Quantum GL fabric and weighs just 2.3 ounces (65 g) in size men’s Medium (photo by Glen Van Peski).
Is an ultralight windshirt an essential piece of gear in an ultralight gear kit? There are good arguments pro and con, and during my testing of the new Montane Slipstream GL Windshirt, I kept that key question in mind.
The Montane Slipstream is an ultralight no frills windshirt; its only real feature is a full-height #3 front zipper. It does have a tape stiffener behind the zipper that doubles as a storm flap, raglan sleeves, standup collar, dropped tail, and the cuffs and hem are elasticized. No hood, no pockets.
The fabric is Pertex Quantum GL (GL means “Good and Light”) which is 10 denier and weighs 0.8 oz/yd2 (25 g/m2), compared to 15-20 denier 0.9 oz/yd2 (27 g/m2) for standard Quantum. Actually, each one is a family of fabrics, but GL is finer and lighter. The shiny surface comes from calendaring to make the fabric stronger.
Specifications and Features
|Year/Model||2011 Slipstream GL Jacket|
|Sizes Available||Men’s XS to XXL (runs about a half size small)|
|Style||Hoodless jacket with full-height front zipper|
|Fabrics||Pertex Quantum GL 10 denier 0.8 oz/yd2 (25g/m2), 100% nylon ripstop, air permeability 1.0 cc max (JIS L 1096/ASTM D737), spray rating 80/20 (JIS L 1092), abrasion resistance 10,000+ at 12.5 kPA (BS EN ISO 12947-2), DWR finish|
|Features||Full-height front YKK #3 zipper, stand up collar, raglan sleeves, articulated arms, elastic cuffs and hem, dropped tail, stuff sack included|
|Weight||Size men’s Large tested.
Measured weight: 2.43 oz (69 g)
Manufacturer weight: 2.3 oz (65 g) size Medium
Front and rear views of the Montane Slipstream Jacket.
I took the Slipstream windshirt on seven backpacking trips and several day hikes during spring and summer 2011, where I encountered cold winds, chilly evenings and nights, rain showers, and snow showers.
The first thing you should know about the Slipstream is that it runs small. My sample is a size Large and it fits like a Medium, which I found to be okay for a windshirt since I frequently wore it over just a baselayer. I have fairly long arms and torso and found the sleeves and body to be long enough. The resulting fit is trim and has the advantage of less flapping in the wind.
The Montane Slipstream Windshirt in size Large can be worn over a thin midlayer, such as the Patagonia Ultralight Down Sweater shown. If you want the windshirt to layer over more than that, you should size up.
The Slipstream does its primary job well. I wore it over a baselayer while hiking several high altitude windy ridges and 13,000- to 14,000-foot (3963- to 4267-m) peaks, such as the ones shown, and it made the difference between chilly versus warm while hiking.
A dynamite combination for hiking in changeable weather is a thin windshirt over a baselayer. A windshirt provides an amazing amount of warmth and comfort for its miniscule weight. The main issue (for me) while summer hiking in such conditions is getting too warm, rather than cold, so I prefer a very thin windshirt. And the Slipstream, like other windshirts, is comfortable when it is cool, overcast, and breezy or windy. When the sun comes out, or the wind stops, the windshirt is too warm and has to come off.
I also found the Slipstream very useful when worn over a thin insulation layer in camp; it makes a significant difference by reducing convective heat loss and holding heat in. I even wore it in my sleeping bag on several nights for extra warmth, and didn’t have any problems with it feeling clammy.
In the field, I found the Slipstream will shed brief rain quite well (left), but wets through fairly quickly. The lack of a hood is a disadvantage in rain. My indoor puddle test (right), where I put the backside of the jacket over a funnel and added a cup of water to create a puddle, was quite revealing. The photo was taken at the beginning of the test, but after an hour all but a few drops of the water had passed through the fabric. Conclusion: the jacket’s DWR treatment provides only limited water-repellency; the jacket is far from waterproof.
Carrying a backpack over the windshirt did not abrade it at all.
Out of curiosity, I performed the same test on the MontBell Tachyon Anorak (discussed below), and found the same result. This reinforces the notion that a windshirt with DWR treatment can shed brief rain, but is not adequate rainwear for significant rains.
So how does the Slipstream compare with using a lightweight rain jacket for windwear, and how does it compare with other lightweight windshirts? For backpackers who insist on minimal pack weight, a windshirt can be left out in favor of using a lightweight rain jacket like The North Face Triumph Anorak (5.85 ounces/166 g for size men’s Large, which is the lightest woven fabric rain jacket currently available) for both windwear and rainwear. I have tested it, and find the Triumph plays the dual role very well.
The main difference is the Slipstream is thinner and lacks a WP/B polyurethane layer, so it has a wider comfort range, meaning it’s more breathable and remains comfortable to wear over a broader range of conditions. I can wear the Slipstream while hiking uphill carrying a backpack and stay comfortable much longer than I can with a lightweight polyurethane laminate rain jacket. The Slipstream blocks the wind and breathes well enough to stay comfortable, much of the time. However, when the breeze stops or the sun comes out, the windshirt gets too warm and I have to take it off.
But in a practical sense, if you don’t need windwear very often, a lightweight rain jacket will suffice. Perhaps the prudent thing to do is pack a windshirt when you expect to encounter conditions where it’s truly needed. And when you get into exactly those conditions, it’s gold.
In areas or seasons where rain is not a big issue, some hikers carry only a windshirt and use it for both wind and rain protection as needed. The Slipstream has a DWR treatment, so it sheds water well and will suffice in short duration showers, but its main disadvantage for such use is the lack of a hood.
How does the Montane Slipstream compare with the MontBell Tachyon Anorak, which received a Highly Recommended rating in a recent Backpacking Light review? The data in the following table tell a lot.
|Manufacturer and Model||Hood||Zipper Length in (cm)||Weight (oz/g) Size Men’s M||MSRP (US$)|
|Montane Slipstream Jacket||No||Full-height||2.3 (65)||104|
|MontBell Tachyon Anorak||Yes||7.5 (19)||2.3 (65)||89|
|The North Face Triumph Anorak||Yes||12 (30)||5.6 (166)||179|
- The Slipstream and Tachyon weigh the same; the difference is the Slipstream has a full-height zipper but no hood, and the Tachyon has a hood but only a short zipper.
- The MontBell Tachyon is the least expensive.
- The North Face Triumph weighs and costs twice as much as the MontBell Tachyon.
A windshirt is a very versatile piece of gear, especially when you hike where the weather is highly variable (I suppose that applies most everywhere). The ideal conditions for a windshirt are some combination of cloudy, cool, and windy; and that occurs a lot where I hike.
The Montane Slipstream is equally as nice as the MontBell Tachyon, so the choice gets down to personal preferences and how you will use a windshirt:
- If you will use the garment only as windwear, the hoodless Montane Slipstream is preferable. I prefer a separate windstopper-type cap, and the full-height front zipper works better for thermoregulation.
- If you use the garment for both windwear and rainwear for brief showers, the MontBell Tachyon Anorak or TNF Triumph Anorak (or other ultralight jacket) is preferable because it has a hood.
- If you want a garment that will suffice for windwear and provides reliable protection in significant rains, an ultralight rain jacket like TNF Triumph Anorak or Marmot Essence Jacket is preferable.
Overall, the Montane Slipstream performs well for its intended purpose. However Montane’s small sizing is an issue. It’s irritating to purchase a garment in your normal size, only to find out that it runs small, and have to exchange it for the next larger size. MontBell has overcome this issue for selling in the US, and it’s about time for Montane to do the same.
A windshirt is really handy to maintain comfort while hiking at high elevations where the weather can be highly variable.