Castelli Alpha Jacket: The PEZ Review

The Alpha jacket is Castelli’s smart take on an old problem – cold weather protection for cycling. It’s design combines a wind & water repellent outer layer with a breathable vest-like inner layer that could very well be the way to the future – here’s the PEZ review.


Having reviewed the Italian brand’s winter kit for several seasons (20142013, 2012, 2011 ) I learned that their place at the top end of the pro bike kit category is well earned – and the best way to stay there is to raise the bar every year.  The quality and design of their gear has impressed me every time (and I still use several of those old test items today), but even more impressive is that just when I think they’ve sent me the best winter jacket I’ve ever tested, they follow it with something just a bit better.

Okay, maybe “best winter jacket ever” is a bit lofty, but their new Alpha jacket does have a lot to offer in cool & cold weather protection.

The big challenge in cold weather kit is how to best regulate body temps while riding – that means keeping the cold out, while allowing enough ventilation to avoid over heating… two traits at opposite ends of the warming – cooling continuum. The industry norm has been to use a combination of fused fabrics consisting of a wind & water (i.e.: weather) repellent outer layer, and a fleecy warm inner to block the cold, trap the warmth; and then ventilate it with a variety of meshes, zipped or velcroed openings, or flaps.

If you’d rather watch than read – here’s the video review:

The Alpha jacket essentially separates these two jobs into distinct layers that co-exist in harmonious equilibrium where the whole is greater than the sum of the parts.   The stretchy Windstopper outer layer that covers most of the main body is water-resistant, and while technically not ‘water-proof’, it does a very good job of keeping water out. I’ve ridden it in rain of all densities, and it really is a wonder of modern technology – easily worthy of a star on the technical fabrics’ Walk of Fame.  It’s not the most breathable fabric in the world, but no matter as it’s best suited to cold weather performance where you want to retain heat.

The kicker of the Alpha jacket though, is its semi-separated inner layer, made of a a soft fleecy brick-weave poly-blend material, whose job is to keep you warm while allowing some airflow inside the jacket to prevent over heating. Instead of being fused to the inside of the Windstopper layer, the inner layer features a vest-like front – complete with its own zipper (which is offset from the outer zipper so the garment front lies flatter) – and is sewn into the garment at strategic points. This allows the front of the jacket to be unzipped as much as you want (even completely open) to facilitate cooling, while the inner layer can stay zipped to maintain core temperatures and prevent too much chill.  The inner layer is not a wind blocker, but really more of an air-trapper.

This inner liner wraps the body front and back, and also extends around the front 2/3 of each sleeve. Body side panels and arm backs are left unlined.

In the back there’s added ventilation across the shoulder blades in form of a large open flap that’s closed at four small points, allowing what looks to be a pretty good amount of exhaust porting when the going heats up. Down below are three good sized pockets that thankfully are structured enough to not sag when fully loaded. There are also two zippered pockets for keys or small items – one conveniently located at the bottom of the front left panel.

I’ve long raved about Castelli’s high winter collars, which on many of their models reach well up my neck – in front and back – to keep me toasty. The Alpha features a new take on the collar though, with an articulated shape that more evenly surrounds the neck when your head is tilted back in the riding position. The back part of the collar is a nice soft fleece.

The waist is also a high-performance design where attention to detail only ups the ante again. The bottom 3-4 inches of the jacket (more in the sides) are made of a strong 4-way stretch lycra that’s shaped sorta like a kidney belt, and secures the whole jacket comfortably from the bottom and prevents any riding up, while allowing all the movement you need to pedal. The same material is used at the cuffs, forming a very sleek fit at the wrists to fit inside any glove, and completely block cold air sneaking into your arms.

Castelli says the jacket can be worn simply over a base layer on most days and you’re good to go. The inner layer lets air pass easily, so exactly how you best layer what’s underneath is up to you. I tend to run on the cool side, and found the Alpha jacket works best for me in November/ December over a long sleeve base and a short sleeve jersey.

And while the Windstopper is very good at repelling water, they do make more rain specific jackets like their Tempesta that I reviewed here.  The Alpha seams are not taped and I’d expect some water entry here and at the cuffs & waistband where the material is not water repellent, but the Alpha still does a good enough job that you can wear it comfortably on misty or light-rain rides.  But it’s better suited for cool to cold, mostly dry days, and can easily be layered over a more robust base for really cold weather.

The fit of my size Small tester was almost jersey-like – snug and form fitting – and like most of Castelli’s gear, it’s cut to fit your riding position on the bike.  The gut stayed put on all kinds of rides, and I enjoyed that general feeling of speed that comes with  Castelli’s more racer-styled fits.

My size Small tester weighed 472 grams, which is not the lightest of my winter jackets, but if you consider it saves the weight of another layer your overall net weight should be lighter.

Finally, at around $300, it’s not exactly cheap – but it is less costly than  jacket AND jersey (at least good ones), but a lot of guys will like the versatility and function of this one.  It comes in black, red, fray, and yellow fluo.

• See more at the Castelli website.

• Check prices at


If I was Castelli, I’d be worried about how to repeat the magic next season, since the Alpha jacket just might raise that bar more than a few notches.

Finally – here’s a nice little video Castelli did that show’s a pretty good lowdown on the Alpha jacket:


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