By Brandon Bilyeu
Hot!
- Alpha Direct fabric keeps you warm and dry
- Soft and comfortable against the skin
- Excellent breathability
- Three rear pockets for storage
- Full front zipper for ventilation and easy on/off with bibs
Not!
- Sizing runs a little big
- No women’s version
- Pockets are redundant if your jacket has pockets
Cost: $160
How obtained: review sample from company
Available: online, retail
Colors: Urban Sage
Website: PRO Alpha Layer
RBR Sponsor: no
Tested: 20+ hours
Sizing: S – XXL
Reviewer Measurements and Fit Comments: 5’10” (178cm), 150 lbs (68 kgs), 33″ (84cm) waist, 38” (96.5cm) hips, 33″ (84cm) inseam, 37″ (94cm) chest. I tested size Medium and the fit was a little loose. To avoid bunching at the waist under an outer layer I would size down.
Alpha Fabric Brings the Warm Fuzzy Feeling
The Pearl Izumi PRO Alpha Layer is designed as a thermal midlayer to keep you warm and dry. It is long sleeve, full zip, and has three rear pockets. Pretty standard stuff, but the differentiator is the use of Polartec’s Alpha Direct fabric throughout most of the jersey. The lightweight Alpha fabric is reinforced under the arms and at the pockets with a heavier fleece construction.
From a distance the PRO Alpha looks like a fuzzy jersey. But close up, the jersey looks like it’s ten years old, has been washed a thousand times, and is so worn out that it is half threadbare. Probably similar in appearance to that favorite jersey in your closet you can’t bear to part with, but the PRO Alpha is brand new and destined to join your list of favorites. Don’t be deceived by the rattly looks, this jersey design is all about thermal performance.
The odd look of the Pro Alpha jersey comes from small bundles of lofted fibers connected to a solid mesh base material. This structure is light and not bulky. The patchwork of fibers and mesh create pockets to hold warm air and voids for moisture to escape through the mesh. The material is also hydrophobic, so it doesn’t absorb sweat, wicks well, and dries fast. It’s also super soft and feels great against the skin.
Versatile Comfort on the Bike
The PRO Alpha is designed as a midlayer to be worn over a base layer and under a jacket. I tested the intended layering configuration as well as wearing the PRO Alpha as my base layer and it worked equally well both ways. As a sweaty guy it performed well as my base layer, wicking sweat off my skin to keep me dry and warm. A snug fit is important for base layer wicking performance and the PRO Alpha runs a little big, so consider sizing down for best results.
The heat retention is top notch. I had to be careful when dressing for a ride to put my jacket on just before stepping outside otherwise I would overheat in the house. The PRO Alpha under a shell easily kept me warm down to freezing. At warmer temperatures the breathability means dumping heat is as simple as unzipping the shell. When climbing or working really hard you can unzip the PRO Alpha to dump all heat, or even take the shell off and stow it in the PRO Alpha pockets. All this to say that the PRO Alpha is really versatile in a wide range of temperatures.
Unfortunately No Women’s Version
While there is no specific women’s version of the PRO Alpha, Sheri tested the men’s version at the same time as me. Comparing notes, it was clear we both had the same experience with Sheri capturing the mutual feelings succinctly with “love, love, love this as a midlayer . . . my go-to for all my winter riding.” Sheri used the PRO Alpha strictly as a midlayer, down to 15 degrees F. Even when on spirited fat bike rides, she remained dry and comfortable.
She also found that sizing runs a little big and could have sized down. Since the PRO Alpha is cut for a man’s body, the chest and waist were roomy, but it did not deter from its excellent performance.
Bottom Line
The PRO Alpha Layer provides nearly perfect cold weather performance in terms of warmth and breathability. The pockets add to the versatility over just a plain base layer. Hopefully a women’s version is in the works.
Brandon Bilyeu is an avid recreational roadie who lives in Regensburg, Germany. He’s a year-round bike commuter and is a mechanical design engineer by trade. Click to read Brandon’s full bio.
I can definitely second on how good Alpha Direct is as a mid-layer. I wear the RAB Alpha Flash jacket https://rab.equipment/us/alpha-flash-jacket under a biking shell and found I am comfortable even below freezing. And it lets the sweat through so it never gets clammy. One of my best winter clothing purchases.
What shells did you and Sheri use? I’m 8 seasons and 3 expensive jackets plus multiple cheap options in and still sweat through everything.
Ornot Magic Shell is really good. With the Rab as a mid-layer, I am good from 45 deg to 30 deg. I find the Alpha Direct really keeps the sweat off the skin. Another idea: For running, I use the Patagonia Houdini shell which is semi-waterproof and my guess is that it would also work well with my Rab mid-layer.
The Castelli ALPHA RoS is also really good. My go to jacket for winter New England multi-hour gravel rides. Good up to 40 deg and down to 15 deg. Looks like it is on sale at the Castelli website.
Thanks for the input PaulyG. Every input helps. I was extra interested in Shelli’s shell choice as she used it fat biking. My winter riding is fat biking and it seems like the speeds of 10mph or less depending on conditions cause technical fabrics not to breathe well enough. Hoping to sew or buy an alpha direct midlayer to help.
I have a Giordana Extreme Light with Alpha (not alpha direct, might cut it out and sew in alpha direct) that doesn’t work. I sweat and the alpha liner material wets out then gets cold. Even at O degrees F with a synthetic short sleeve baselayer I sweated through through and got cold arms. I had forearm, bicep, and lower back zipper vents installed and still no luck.
I also have a Castelli Perfetto Ros 2 Convertible that I paired with a synthetic short sleeve, and Eddie Bauer grid fleece at 4F and I had frost inside my forearm sleeves and around the core vents I had open.
3rd jacket was Bontrager OMW with 37.5 technology and that still wets out and frosts inside with simple thin longsleeve baselayer at 5F.