Castelli wasn’t satisfied with the status quo, so they designed the all-new Alpha Jacket. Built with Windstopper fabric and a whole lot of attention to detail, this may be the pinnacle of cold-weather riding jackets.

Castelli Alpha Jacket Features:

  • Articulated collar delivers comfort on or off the bike
  • Windstopper® 150 stretch fabric is windproof and water-resistant
  • Separate insulating layer ensures better ventilation and breathability
  • Asymmetric external YKK® Vislon zipper slides easily and lays flat
  • Raw edge waist lays flat and moves with you
  • Raw edge wrist cuffs lay flat for a perfect interface with gloves
  • Castelli silicon text gripper at waist
  • 3 rear pockets, one zippered with reflective webbing
  • Price: $349.95
Castelli Alpha Jacket Review

A little dirt road down by the river suits me just fine.

Alpha Jacket Delivers Legendary Quality

That red scorpion is an icon in the cycling industry. For years, Castelli’s Gabba has been worn in the pro peloton as unbranded all-weather gear. Continuing along those lines, Castelli has once again combined forces with W.L. Gore to conjure up a spectacular cold-weather riding jacket in the all-new Alpha.

Not satisfied with their existing jackets or other winter-capable jackets on the market, Castelli designers really obsessed over every thread of the Alpha Jacket — and it shows.

For starters, using Windstopper 150 fabric is a fantastic choice. This lightweight, breathable, wind and water-resistant wonder fabric really sets the bar as far as functional protection. While it’s not as waterproof as say, GORE-TEX, it breathes a heck of a lot better. That’s an unfair comparison actually — I’ll say it breathes as well or better than the Polartec NeoShell-clad Sugoi RSE Jacket (one of my favorites for really wet rides) while remaining highly water-resistant.

The fit is spot-on for Castelli with the size Large offering my 5’11”, 175 lb. frame the perfect bear hug — not too tight, but nothing extra to flap in the wind.

I’ve now worn the Alpha Jacket with a variety of base layers. Let me start with the long-sleeve Castelli Uno Plasma base layer. I opted for this layer on one cold ride in the mid-30’s. Pulling the jacket on with a long-sleeve base layer, like the Uno Plasma, is a bit of a chore. You do have to hold the sleeve in place while slipping on the sleeves, or it will get all bunched up. I also used the Craft Active Extreme Windstopper base layer and it slipped on a bit easier with less bunching.

On warmer rides, I wore a short-sleeve jersey or a sleeveless base layer underneath the Alpha.

Castelli Alpha Jacket Review

Vest mode allows for increased airflow during long climbs.

The block-pattern fleece lining is another highlight of this jacket. That same pattern is fairly common in some of the highest-performing fleece layers (like the Patagonia R1), but hasn’t caught on in cycling. Castelli knows the wiser and has employed this aboard the Alpha. That lightweight fleece delivers warmth and the block channels absolutely aid in breathability when pumping out the watts or as the weather warms. The back vents allow heat to dissipate as well — more evidence of a well-executed jacket.

Built with an integrated vest, the Alpha really shines when temperatures climb north of 50-degrees or on extended climbs. It keeps the jacket from flapping around and maintains just enough core warmth so as not to shock the system with an influx of cold air.

The three rear pockets are a little small, but there are 5 total pockets — including a zippered pocket up front and on the backside for important items.

The collar is nice and snug with a comfortable raised back collar for added warmth and comfort in and out of the saddle. With lazer-cut cuffs and hem, the elements are kept at bay without any added bulk. Gloves slip right on top for a weather-proof barrier that’s spot on.

I have not had an opportunity to wear the Alpha in really bad weather — just cold (35-50 degrees) and a few sprinkles — but, Windstopper fabric is dependable at shedding the worst of Mother Nature. A faucet test has yielded waterproof performance, so I’m confident it will withstand more than the light rain I subjected it to.

The Good

  • Windstopper is the pinnacle of performance
  • Soft, low-profile cuffs fit well under gloves
  • Big zipper pull
  • Easy access to rear pockets
  • Efficient fit that stays put
  • Built-in vest keeps things in place and keeps extreme cold at bay
  • Back vents — ’nuff said

The Bad

  • Fleece-lined sleeves bunch up some long-sleeve base layers
  • Collar is a bit snug and hard to fully zip on the fly

The Bottom Line: Castelli Alpha Jacket

With enough warmth and gobs of weather protection, the Alpha Jacket wears like a beefed-up jersey. I can’t praise Windstopper fabric enough and the overall fit and finish of this jacket is impeccable.

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About Author

A native of the Pacific Northwest, Jason quickly developed a love for the outdoors and a thing for mountains. That infatuation continues as he founded this site in 1999 -- sharing his love of road biking, mountain biking, trail running and skiing. That passion is channeled into every article or gear review he writes. Utah's Wasatch Mountains are his playground.

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