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Castelli Alpha Ros Jacket - Women's
Sale $262.46$349.95 25% Off

Item # CST00JB

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Item # CST00JB


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

Tech Specs

Gore Windstopper 150
Waterproof Rating:
double front opening
3 rear, 1 zip side
rear pockets
Claimed Weight:
Recommended Use:
road cycling
Manufacturer Warranty:
1 year

Size Chart


Women's Cycling Apparel












































Note: Castelli has a "Euro" slimmer fit. We suggest ordering at least one size larger than your normal US size.
How to Measure:
For best results, take measurements over your underwear.
Measure under your arms, around the fullest part of your chest.
Natural Waist:
Measure around your natural waistline, keeping the tape a bit loose.
Measure around the fullest part of your body at the top of your legs.
Using pants that fit well, measure the crotch seam to the bottom of the leg.

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