The Arc'teryx Rho LT Bottoms were an instant favorite among testers at OutdoorGearLab. It's supremely comfortable; the brushed fleece interior is the coziest next to skin feel of any bottom we tested. The polyester/elastane blend offers the most durable fabric we tested and is extremely stretchy to boot. Even though it's advertised as LT — Arc'teryx code for lightweight — it is one of the warmest bottoms we tested. Versatile and comfortable for all-day wear, it's a perfect all-around pant for cool to cold seasons and the only pant that is handsome and inconspicuous enough to wear as an outer layer, like a running tight. With a superb fit, super comfy fleece-lined fabric, terrific quality, great functionality, and solid warmth, the Rho LT was a tight contender for the Editors' Choice Award. We found that we loved them as a stand-alone layer for trail running in the winter and resort skiing. These bottoms are versatile and will serve you well in most endeavors, except for warmer weather activities that are highly aerobic, like spring backcountry skiing.
Arc'teryx Rho LT Bottoms Review
Cons: Pricey, below-average breathability
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Our Analysis and Test Results
A comfortable, warm, and versatile bottom that delivers reliability and our favorite fit, the Rho LT is at home in cold alpine conditions, shoveling the driveway, and enjoying a good book on your rest day at the lodge all the same.
These are advertised as LT — or lightweight — but pack a punch for warmth. The 150 g/m² weight of the synthetic, proprietary Torrent fleece is slightly thicker than a traditional Merino midweight, but supply slightly more warmth. The brushed fleece interior is warm and super cozy next to skin. These are our go-to bottoms for low output activities in cold weather, like resort skiing or winter camping.
The Rho LT was easily warm enough to be our only layer underneath a pair of non-insulated ski pants. Although they are advertised as a lightweight, we wouldn't suggest these for lightweight use, as you'll likely end up hot and sweaty.
For a thicker synthetic layer, these breathe impressively well. The Torrent fleece does a wonderful job of wicking sweat to the outside of the fabric and drying quickly. They do tend to hold onto water once moisture settles into the fibers, though, as we experienced in our drying test. We put the breathability of these pups to the test trail running in the mountains overlooking Salt Lake City with temperatures varying from the 40s down to single digits. These tights did a great job balancing warmth and keeping us dry. Hill sprints in 40-degree weather were the upper limit of warmth and output for these — they weren't able to wick quite as fast as we were creating sweat, so they held onto some moisture — but dried quickly once we came to a rest. Running in colder weather, they did a terrific job of staying warm and breathing well. If these were more breathable and wicked slightly sweat better, they'd be unstoppable.
Comfort & Fit
Ooooh, are we excited to tell you about the comfort and fit on these! One word - superb! An extremely stretchy but tight and comfortable fit paired with purposeful design and sleek look earn our favorite fit for these bottoms. They wear like a second layer of skin. Not the easiest to pull on, they are snug, and the fleece lining is sticky — but once they're on, it's like they were laser molded to your bottom half. The close fit and stretch allow them to move freely with you, and the synthetic fabric wears well all day. They were particularly impressive use after use, not stretching out like a typical Merino layer.
The synthetic fabric is a blend, 84% polyester/ 16% elastane, creating a sleek and smooth outer fabric that slides easily inside of a layer. The Arc'teryx Torrent fleece is an ultra-cozy soft brushed fleece lining that feels like heaven next to your skin. The waistband is comfortable and simple, there is no crotch sag, and a simple and technical seam pattern incorporates a gusseted crotch that runs on the inseam down to the knees for ultimate mobility. These are a bottom layer that doesn't offer a fly, so you'll be pulling these bad boys down for backcountry relief. The lack of a fly is our only qualm with these nearly perfect fitting bottoms.
Another category winner, the Rho LT proved themselves as the most durable bottom we tested. Made of thicker synthetic material, they showed some surface wear in our brutal and merciless abrasion test that is notorious for blazing holes through base layer fabrics. Synthetic fabrics are generally more durable than fragile Merino, so all of the synthetic bottoms that we tested did well in the durability category. These bottoms aren't cheap, but they will serve you for years of hard use. We wouldn't suggest walking through a briar patch or a barbed-wire fence wearing these, but we wouldn't recommend that in most circumstances.
While these aren't the most expensive bottoms in our review, they are near the top of the list. Although these are a pricey pair of bottoms, we feel that with these, in particular, you get what you pay for — a quality and versatile pair of bottoms that are going to serve you for years of use and abuse.
We are in love with these bottoms for cold season endeavors. Their comfort, fit, quality, and versatility to perform well in varying activities and temps get two thumbs up from us. A thoughtful and handsome design; these are the only bottoms we felt comfortable wearing as a stand-alone layer for trail running. A great pair of bottoms if you need a durable pair of bottoms for venturing out into cold temps and appreciate quality and extreme comfort.
— Roland Mott