Review: Arc’teryx Zeta SL Rain Pants

Rain can feel inevitable when hiking in the Pacific Northwest, especially in the early summer months. Like many backcountry travelers, I don’t regard rain as a particular friend of mine when I’m hiking. But, at the same time, it’s what makes the understory in the PNW so lush and green. So, I don a good pair of rain pants and make my peace with it. This summer, those pants have been the Arc’teryx Zeta SL.

‘Emergency’ protection that can travel for miles:

Arc’teryx bills the Zeta SL pants as ’emergency’ rain protection and I think that’s kind of funny. For one thing, I am too poor for a $250 backcountry rain insurance policy. For another, years ago I reviewed some emergency rain gear that was literally see-through. That’s what I would call an emergency rain suit.

What they’re going for, though, is a piece of fast-and-light, minimalist rain gear that doesn’t take up bulk in your pack and still wears decently. The ‘SL’ in their naming system comes from fast-and-light, and I like to think that the ‘Zeta’ signifies that it’s meant to be a piece of last resort. It doesn’t need to be, though. I put some mileage into the Zeta SL’s while hiking the Loowit Trail which circumnavigates Mt. St. Helens during a pitiless soaking June rain. The Zeta’s held up.

The foundation for the Zeta’s is Gore-Tex’s well-known Paclite fabric. Generally speaking it’s one of Gore’s more affordable fabrics, and while it’s quite waterproof it doesn’t breathe as well as their Pro or Active lineups. But, it’s lighter, has a nice soft handle, and packs down well – making it perfect for something that you plan to mostly keep in your pack. And they really are pretty minimalist: there are no pockets to be found.

That Paclite is bonded to Arc’teryx’s proprietary ‘N40r’ fabric, which is really just a 40-denier nylon fabric treated with a DWR. That 40-denier weave is nice and strong and consistent with what you’d find on most shells (just search ’40D’ on our website). There are thicker weaves for heavy-duty pieces and lighter ones for ultralight pieces, and honestly I’m happy to find a 40D weave on a fast-and-light ’emergency’ piece. It’ll translate to more longevity for the product.

There are a few other elements of the construction that are worth noting. For one thing, Arc’teryx has the thinnest seam-taping margins in the industry; so while these pants are fully seam-taped, they save weight by eliminating excess material.

The pants have zippers that go up just above the knee, which Arc’teryx calls a 3/4 zip but seems shorter to me. The zipper is very narrow-gauge and the zipper pull doesn’t even have a tag to grab. It definitely screams ‘lightweight.’ The design works well and I could fit my heavy mountaineering boots through the opening they created. However, I do see this as the pants’ most likely failure point: you have to be really careful with those ultralight zippers over time to preserve their longevity. Don’t force them, and keep them clean. This is particularly true on a pant since the bottom half of the zipper spends a lot of time around dirt.

You will find a conventional fly zipper and snap-button closure. There’s an integrated internal belt which is pretty interesting though. It’s basically a narrow, roughly 1/2″ wide webbing band with a simple friction lock on your right hip. It works very similarly to tightening a tie down or NRS strap, except your waist is the load being secured. I truly did not think it would work and thought the pants would be around my ankles all day. However, to my delight, it worked really well and didn’t creep loose as the day went on. I was so impressed with that.

What really makes these pants shine is the tailoring. Arc’teryx is spendy stuff, and really what you pay for is the design expertise. I have to say, these pants really fit the bill for wearing comfortably and actually looking decent. I don’t usually care how rainwear looks, but my hiking partner (wearing a pair of baggy Gore-Tex rain pants from another brand) commented on how sleek the Zeta SL’s look. He’s right – and it’s just tailoring. That said, the tailoring minimizes excess material and helps the pants hike well. The gusseted crotch and articulated knees are also important in helping them move well.

Overall I was impressed with how they held up on the trail. They did hike very well and didn’t feel too constrictive or overly baggy, which is a careful balance. I did find the pants a little tight in the thighs, and if I had that problem I imagine a decent number of thick-thighed hiker/biker types could as well, and you don’t want to chafe your way through the rain. Not also that there are no lace hooks to keep the hems down, but I did not really find that I missed them; the pants flare slightly at the bottoms and cover your boots well and stay in place.

There were some slight casualties to the fabric as I hiked, but in fairness I took these pants through some really punishing terrain. Mt. St. Helens is so rugged and much of the trail is just scrambling over volcanic stones that used to live deep inside the earth. As a result, I picked up some snags in the fabric. The Zeta SL’s don’t have a kick patch, but the instep is reinforced and that did help keep me from putting a hole through them. I could have prevented those by wearing gators, and I really should have been. I don’t fault the Zeta’s for that.

One concern that I do have is some partial delamination that’s occurred on the cuffs, evidenced by some slight bubbling. It’s mild, and functionally it would not play a major role in keeping me dry in that area. But, it’s not what you want to see. Arc’teryx’s warranty people have been great in the past and if this progresses it’s a service that I would use.

The Good

• Great tailoring and fit
• High-quality materials
• Webbing belt worked shockingly, delightfully well
• 3/4 zips are more like half zips but work every bit as well

The Bad

• Instep would benefit from a more truly abrasion-resistant layer
• Zippers are very narrow-gauge and may have longevity issues
• Some delamination is evident on the cuffs of the pants

The Bottom Line: Arc’teryx Zeta SL Pants

When I first saw these, I assumed that they were going to be delicate, just-in-case emergency rain pants that couldn’t handle much more than sitting around in the rain. I was truly impressed with how they performed as a true all-day backpacking rain pant. The rainy Pacific Northwest is as good a proving ground for rain gear, and the Arc’teryx Zeta SL’s were up to the challenge.

Buy now: Available from Backcountry.com