The Outdoor Research Alpine Onset bottoms take home our Editors' Choice Award for the best overall base layer bottom. A prestigious award for the new kid on the block, but we think it's well-deserved. A merino layer bottom infused with nylon and spandex to increase durability and stretch we find this bottom to be our go-to layer for all-around use in a variety of activities and conditions. Its fabric is lightweight and extremely breathable but packs a midweight punch when it comes to warmth. A superb ability to wick away sweat and dry quickly, these bottoms will keep you dry and comfortable from cold resort days to warmer weather backpacking. Did we mention, they don't stink, and they fit like a glove? That too.The Alpine Onset was not the only impressive model in our test, and it fought hard to earn our highest award against the warmer and more durable Arc'teryx Rho LT and SmartWool Merino 250. In the end, our athletic testers preferred the versatility offered by the more breathable, less warm Alpine Onset.
Outdoor Research Alpine Onset Bottoms Review
Cons: Not super durable, not for super cold
Manufacturer: Outdoor Research
Our Analysis and Test Results
Winning our Editors' Choice for overall best base layer bottom, the Outdoor Research Alpine Onset combines a light and comfortable merino wool with an outstanding ability to insulate when it's cold, wick sweat and stay dry during high output activities, and do it all without holding onto a memory of our hard work through stinky sweat.
As far as weight, these are the lightest bottoms we tested that fall into the midweight category. Even though they are lightweight as far as grams, they deliver a traditional midweight insulation value. They kept us warm winter trail running and skinning in sub-freezing temps, but the beauty of midweight is their versatility to keep you comfortable in a wide range of temperatures. These bottoms are stellar in cold conditions when you are using a lot of energy and creating a lot of heat.
If warmth is a non-negotiable for you or you spend time in extremely cold environments, we would suggest a warmer alternative like the SmartWool Merino 250 or the Arc'teryx RHO LT bottoms. The Alpine Onset bottoms are ideal for mid to high output activities in cool to cold weather. Perfect for winter trail running, fall backpacking, and backcountry skiing.
These pups earned their spot as lead sled dog when it comes to this skillset. They breathe like the Dalai Lama, wick sweat away from the skin like a true champ, and dry super fast. They have a nice snug fit which aids in breathability as it allows space in between the base layer and the outer layer for water vapor to dissipate.
These bottoms excel when breathability is a necessity. Working up a sweat skinning what seemed like endless miles of vertical terrain, these bad boys didn't even blink an eye; there wasn't as much as a hint of sweat on them as they seem to dry faster than you can provide sweat.
Comfort & Fit
Another area that these bottoms knock it out of the park! The soft and cozy merino wool is delightful next to skin, and these things fit like a dream. Nice long legs that run snug through their length and don't seem to stretch as easily as the SmartWool Merino 250 bottoms. A single flatlock seam runs the length of the leg and joins a simple and comfortable design in the crotch. Outdoor Research bypassed a gusseted crotch while still maintaining mobility by simply moving the inseam forward; a smart and simple way to minimize seam lines while maintaining mobility.
These bottoms feel like someone painted them onto your legs, they are efficient while flying under the radar. We like that humble quality about them. A nice balance of tightness in the ankle cuff allows them to slip easily over your heel but hugs your legs nicely and allows them to be layered under a pair of jeans without the legs bunching up onto your calf.
A low profile waistband is comfortable and does a good job of not rolling in on itself after long days of use. The Arc'teryx RHO LT are the other bottoms that have as impeccable of a fit and as high of an overall score as the Alpine Onset bottoms.
This is the chink in the armor of this baselayer warrior. It crushes in every department, but at the end of the day, it's still merino wool which by nature is simply not a tough fiber. Think of it as a Ferrari - it is impeccably made and performs at the highest levels, but you're not going to take it to the demolition derby. Outdoor Research does give it a leg up by reinforcing the merino fabric with polyester for increased durability which is a nice sentiment but doesn't make it unstoppable. It is a fine fiber and generally pretty lightweight material that just wasn't built for the demolition derby; this is why we wear it underneath our pants.
Overall, it fared pretty well for merino wool. It didn't pill after multiple washings and wearings and was in better shape than other merino layers in the abrasion test. The abrasion test created a very small hole, which was better than the SmartWool Merino 150, which blew a hole right through the fabric with no questions asked. For a merino layer, we'd say it falls right in the middle of the tough guy spectrum. It's not getting shoved in lockers during the passing period, but it's also not the captain of the football team. As always, merino lasts longer when it is properly cared for, washed minimally and laid flat to dry.
This layer exists to be used in athletic endeavors - mastering a balance between insulation in cool to cold weather and breathing when you crank up your heart rate. Although its athletic ability shines, it feels equally at home stoking the wood burning stove in the hut or nestled inside a sleeping bag. This is our Editors' Choice Award winner because of its high performance, impeccable fit, but most of all its versatility. This is a perfect weight and high performer to serve you in full on backcountry ski missions, demanding ice climbing, summer backpacking, fall river trips, and everything in between. If we could choose one layer to have as our adventure buddy year round, this is it.
At $89 it sits right in the middle of the price range when compared to other merino layers of equal stature. We think that the quality and versatility of these bottoms are worthy of the price. If you take care of them, they'll last you for years and your price per use will even out.
Sporting a thoughtful design, handsome look, and excellent fit, the Outdoor Research Alpine Onset Bottoms are a practical choice if you are looking for a versatile layer that is at home in demanding situations in cold weather as well as endeavors across all seasons. A great, light, and packable go-to piece that will keep you company on winter trail runs, fall fly-fishing trips, and any other adventure outside of polar exploration you can dream up.
— Roland Mott