Rab Viper Jacket

Rab Viper Jacket

Size: Large

Weight: ~415 grams

Fabric: eVent DV Lite

FEATURES

• eVent® DV Lite 2.5L fabric
• Helmet compatible hood with wired peak
• 2 YKK Aquaguard® zipped A-line pockets
• 1 YKK Aquaguard® zipped chest pocket
• YKK Aquaguard® front zip, internal flap, rain drain
• Tricot lined collar
• YKK calendered pit zips
• Velcro® cuffs, hem drawcord
• Reflective trim
• Fit: Regular

MSRP: $260

Days Tested: 12

The Rab Viper is more different than similar to the other two “super breathable” hard shell jackets I’ve recently reviewed, the Arc’teryx Beta FL and the Westcomb Switch LT Hoody.

In effect, the Viper toes the line between a hard shell jacket and a raincoat, and it comes in at a very attractive price. With a MSRP that is nearly $200 less than the Arc’teryx Beta FL, the Viper shouldn’t be overlooked if you’re in the market for a high-performance jacket.

There are some performance tradeoffs to go with the Viper’s more palatable price tag, but I’ll go over those below and hopefully put you in a position to decide whether the Viper makes sense for you.

Fit

The Viper’s fit is very similar to the other jackets in the test. I tested a size large, which is a bit too big for me, but I would wager that the Viper has a bit more room in the arms than the other two jackets.

The Viper is still what I would consider a slim, alpine fit, though. It seems more geared toward throwing on fast when the rain comes rather than fitting very trim to wear all day.

The hood is large enough to fit over a ski or mountaineering helmet.

Features

Two large, harness-compatible main pockets and a large napoleon chest pocket provide A LOT of room for storage in this jacket. Skins and lunch will easily fit at the same time.

Like the Westcomb Switch LT Hoody, the Viper features pit zips. (The Arc’Teryx Beta FL does not.)

The hood has a wired brim, which allows for easy, personalized configurations. Every time I take the Viper out of my pack, I do have to readjust the wired brim since it gets shifted around in my pack, but it’s no big deal.

Overall, this is a minimalist jacket—just like the other two jackets in this test.

Fabric

The Rab Viper features eVent’s new DV Lite laminate, which is a 2.5 layer version of their standard 3L laminate (more details on this below). The jacket performs well, but I have a hard time picking it out of the closet over the Arc’teryx Beta FL or the Westcomb Switch LT Hoody because of the feel of the 2.5L fabric—the price-point construction does look and feel cheaper than those 3L jackets that cost about $170-$200 more than the Viper.

There is also a noticeable decrease in breathability without that tricot third layer. The tiny weight savings gained in 2.5L construction is, for me, lost in the performance and comfort compromises associated therein, so you’ll need to decide whether the price savings justify those compromises.

eVent’s DVL stands for “Direct Vent Lite.” This fabric is a 2.5 layer fabric, meaning it is made up of the face fabric, eVent’s ePTFE waterproof / breathable membrane and a protective scrim that is printed directly on the ePTFE (that “half” layer, the ‘.5’ of the ‘2.5’L).

The eVent fabric used in this jacket is an air permeable fabric, like Neoshell, although the inner workings of the two membranes are quite different.

The fabric overall has performed well in a variety of conditions, but there are two issues that I have with this fabric: (1) the clamminess that is readily apparent when the fabric touches bare skin (this happens often when I wear a short sleeve base layer under the shell) and (2) the decreased breathability from the lack of a tricot layer in the shell fabric.

These are the two main tradeoffs of using a 2.5L fabric instead of a full 3L fabric. Are they tradeoffs that make sense in order to save a few hundred dollars over the other jackets in this test? In many scenarios, I would say yes.

The discomfort of the 2.5L fabric on bare skin is not that big of a deal for me. I don’t like it, but if I was wearing this jacket primarily as a rain jacket in a place like Colorado, where rain storms are typically brief and are followed by great weather, this jacket could be an excellent option.

But if you’re looking to buy a jacket to wear for longer periods of time (e.g., ski touring, or in a few hours of light rain such as you might encounter in wetter climates), it won’t be as comfortable as a 3L jacket. So if you think of 2.5L fabrics in general and the Viper in particular as an emergency rain jacket, I think it is a great option that won’t break the bank.

Breathability

I found the Rab Viper to be less breathable than the Arc’teryx Beta FL and the Westcomb Switch LT Hoody, and I attribute this purely to the fact that this jacket is a 2.5L rather than a 3L jacket.

In high-output activities in the Viper, I often got sweat buildup inside of the fabric, which is indicative of overwhelming the breathability of the fabric. And this often occurred sooner and at lower activity levels than it would in the other jackets.

It is possible that the Viper breathes similarly to the Westcomb Switch and Arc’teryx Beta FL, and it only seems to be breathing less effectively because the sweat is much easier to feel on your skin before it escapes, since it isn’t absorbed into the inner liner.

Either way, the Viper seems to breathe slightly less efficiently than the Beta FL and Switch jackets.

Breathability & Product Care

Another consideration with eVent DVL is the care regimen that must be followed to ensure the fabric stays waterproof.

The ePTFE is unprotected in the Viper’s DVL 2.5L fabric. Unlike 3L jackets, there is no tricot layer to protect the ePTFE layer; it is directly exposed on the inside of the jacket, and therefore susceptible to fouling. So it is very important to keep the jacket clean to eliminate the risk of hydrophobic “bridges” caused by sweat and grime that will allow water to get through the fabric. 

I would recommend washing any eVent jacket in Nikwax TechWash every couple of months, and more often than that with more frequent use. You can substitute TechWash for a mild detergent, but it is very important to not use fabric softeners because they will destroy your DWR.

I would also recommend a similar wash regimen for a jacket like the Westcomb Switch LT Hoody that is made from Neoshell, though it probably doesn’t need to be washed quite as often because it is made of polyurethane rather than ePTFE.

Comparisons

As I’ve said, the Viper performs well, and may make far more sense than the other two jackets depending on your budget and how you intend to use the jacket. But the biggest advantage of the Viper over these other two jackets is the price savings. So I’ll wrap this review up by making a few head to head comparisons:

Rab Viper vs. Arc’teryx Beta FL

The Arc’teryx Beta FL has a slight edge in breathability, but a larger edge in general comfort because of its 3L construction. It also has a slightly more anatomical fit than the Viper, and is lighter and packs down smaller than the Viper.

But the Rab Viper is $190 cheaper. So if the price is important, I would pick the Rab for ski touring, mountaineering and backpacking. But if price is less of a concern, the Beta FL wins, unless you’re committed to purchasing a jacket that has pit zips.

Rab Viper vs. Westcomb Switch LT Hoody

The Viper has a very slight edge in weight over the Westcomb Switch LT (~30g), while the Westcomb breathes noticeably better and is more comfortable in general because of its 3L fabric and slightly better fit. But the Rab is $170 less expensive, and will certainly do the job as an emergency rain jacket / backpacking jacket.