CastelliAlpha RoS Jacket - Women's

Whatever winter dishes out.

We're well aware of the additional hardships and discomfort associated with riding during the winter months. We certainly don't want our apparel to be our excuse for not getting out, so if you're in the market for a thermal jacket that offers excellent protection during times of precipitation, take a look at the Women's Alpha ROS Jacket from Castelli. It blocks the weather, but the outer layer and insulating layer are separate, so you can choose how much insulation and protection you need, even mid-ride.

Part of the reason dressing for winter riding is so difficult is that we need to stay warm for most of the ride but if the pace picks up or there is climbing involved, we'll quickly turn into a sweaty mess leaving our muscles feeling stiff and us shivering for the rest of the ride. From working with pros and from other garments it's created, Castelli learned that a jacket with wind and water protection was necessary, but that protection could occasionally be too much. The Alpha ROS is prepared to pamper you with warmth and dryness this winter riding season.

Castelli uses the requisite Windstopper 150 membrane and thermal insulation in the Alpha, but does so in two detached layers allowing each piece to do what it does best and further regulate temperatures while climbing. As you heat up, unzipping the shell lets the wind hit the jacket's thermal layer cooling you off gradually instead of with an unmitigated arctic blast. The thermal layer insulates while breathing quite well so you get more of a thermostat and less of an on/off feel. It's able to manage moisture continuously as you summit the climb keeping you dry as possible. At the top, simply zip up and head down without teeth rattling or shivering throwing you off your lines through corners.

On the plunge down, you'll appreciate the Gore Windstopper 150 membrane. The windproof three-layer, four-way stretch knit fabric with a water-resistant DWR coating keeps wind out and precipitation at bay. You'll want this jacket just as much on solo base mile rides through the valleys as you will on tempo group rides over rolling terrain. The ventilating back panels resist trapping heat to further promote cold-weather comfort.

The Alpha ROS has an aggressive race fit more reminiscent of a jersey than a jacket, and it leaves just enough room for a base layer underneath, which is all you'll really need since the thermal layer does such a wonderful job of providing warmth. Castelli cuts the jacket to accommodate your arms, chest, and shoulders while you're in a riding position. The only disadvantage is it may feel tight across the chest when you're off the bike, but, once you're back in the saddle, it all-but disappears.

The Alpha ROS features raw-edge construction at both the waist and wrists. This allows the sleeves to integrate cleanly with gloves without bunching fabric, and it keeps the hem in place. The waistband also features silicone grippers, anchoring it and maintaining coverage as you ride. The collar is engineered to avoid creating a wind chute behind your neck while you're in the saddle, and three jersey-style rear pockets add easy access to nutrition mid-ride. A final, zippered front pocket adds an element of security to keep your valuables safe.

  • A race cut cycling jacket for the heart of winter
  • Windstopper 150 membrane shields against the elements
  • Maintains breathability and stretch for comfort
  • Outer and thermal layers unzip separately
  • Raw cut hem and cuffs reduce bulk and lie flat
  • Three pockets supplemented by a zippered side pocket
  • Race fit is sleek with just enough room for a base layer
  • Recommended for temperatures hovering around freezing
  • Reviews
  • Q & A

Awesome jacket

  • Familiarity: I've used it several times
  • Fit: Runs small

I am 128 lbs, 5’5”, I usually am size small. But in this jacket small was too small. I got a medium instead. This jacket really does what it says. I am the type of person who is always cold. I wore it in 32 degree Fahrenheit weather. I wore a base layer and tank top. Also had fleece neck muff and gloves. Once I got going I was comfortable, not cold. I have also worn this jacket with only a tank top on a 52 degree Fahrenheit day. I’m sure I’d be fine if it got even warmer and I wore it unzipped. The pockets, fit, sleekness and style of this jacket are superb. Was more expensive that others, but very much worth it. This jacket can take me from fall, through winter and into spring. It fits like a cycling jacket, close to body, fitted, not exactly super snug like a cycling jersey would be, this is not a problem for me.

Nice, but not perfect for me

  • Familiarity: I've used it once or twice and have initial impressions
  • Fit: Runs large

I wore this jacket for the first time the other day in fridgid temps with a long sleeve base layer as well as a thermal long sleeve jersey. I was comfortable while riding, but unfortunately am not completely loving the fit off the bike (maybe there is extra room in the mid section to allow for the added attached inner warm fabric to fit properly under the jacket?). Thinking it is more of a relaxed fit rather than a racer one. Bought the medium (5’3”, 117 lbs.)

Nice, but not perfect for me