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Castelli Alpha RoS 2 Jacket Men’s



Exceptionally versatile winter windproof jacket that's warm and highly water resistant
Versatile double-layer construction
Excellent Windstopper fabric
Stretchy enough for a close fit
Among the more expensive options out there
543g Recommends

This product has been selected to feature in recommends. That means it's not just scored well, but we think it stands out as special. Go to recommends

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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The Castelli Alpha RoS 2 Jacket is an exceptionally good windproof for cold weather with a few tricks up its sleeve – literally, in one case – that add to the performance.

Ash reviewed a previous version of the Alpha RoS a couple of years ago and praised it as an all-in-one winter jacket that's hard to beat. I agree. It has been updated with a handful of genuinely useful new features that I'll come to in a mo.

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The exterior is made from Gore-Tex Infinium Windstopper 150 which, as the name suggests, prevents cold air from blowing in. You don't need me to tell you how important that is when the temperature is close to zero and you hit the longest, fastest descent of the day. It stops that wind chill wrecking your fun.

2021 Castelli Alpha RoS 2 Jacket Mens - Gore-Tex logo.jpg

There are a couple of other things you need to know about Infinium Windstopper 150. First, it's highly breathable so you don't get that boil in a bag effect when you hit the climbs.

Second, although Gore doesn't call it waterproof, Infinium Windstopper 150 is way more water-resistant than you might expect, a durable water repellent (DWR) coating helping out the internal membrane in this respect. Castelli has added more external taping to the seams over the shoulders than on previous versions of this jacket, but the other seams aren't taped so water can creep through. Even so, the Alpha RoS does a great job of keeping road spray and short showers out. You can't dispense with a waterproof shell if heavy rain is forecast, but I've stayed perfectly dry in changeable conditions.

2021 Castelli Alpha RoS 2 Jacket Mens - shoulder.jpg

Another crucial element of the Alpha RoS 2 is the clever double-layer construction. Opening the front reveals inner panels that attach at the sides of the jacket and zip together in the middle. Effectively, it's like having the front half of a gilet attached in there (check out the pics – they explain it far better).

2021 Castelli Alpha RoS 2 Jacket Mens - inside panel.jpg

This inner layer is fleecy polyester that provides extra insulation. The same fabric is used inside the sleeves, extending around about two-thirds of the circumference of your arms.

2021 Castelli Alpha RoS 2 Jacket Mens - inside.jpg

This double layer at the front gives you a few different options. You can have both closed up when you want maximum warmth and protection. You can open the outer but leave the inner done up when you hit a climb and want to let humid air out and cool air in. You can even push the inner layer to the sides and zip up the outer if you want that windproofing but don't need so much insulation on your chest.

2021 Castelli Alpha RoS 2 Jacket Mens - collar.jpg

The bottom line is that this structure isn't a gimmick, it works really well, allowing you to adjust things according to the conditions, the terrain, and your riding intensity, without the jacket as a whole flapping about or the need to stop and add/remove layers.

2021 Castelli Alpha RoS 2 Jacket Mens - hem.jpg

One new feature with this incarnation is the double-layer cuff which is similar to designs you'll find on quite a lot of outdoor coats. Essentially, inside the Infinium Windstopper 150 layer there's a second, more stretchy cuff. The inner cuff goes closest to your arm, tucking inside the top of your glove, and then the Infinium Windstopper 150 layer goes on the outside. The idea is that any water that runs down the outside of the Windstopper fabric doesn't simply get funnelled into the top of your glove. It works really well so it's worth taking a few seconds at the start of your ride to get everything arranged properly.

2021 Castelli Alpha RoS 2 Jacket Mens - cuff inner.jpg
2021 Castelli Alpha RoS 2 Jacket Mens - cuff.jpg

Up top, the neck is tall with a comfortable fleecy section around the back, while stretchy panels at the waist – made from the same fabric as the inner cuffs – ensure a close fit in that area, and a silicone gripper holds the hem in place.

2021 Castelli Alpha RoS 2 Jacket Mens - gripper.jpg

The Infinium Windstopper 150 itself is also stretchy – particularly across its width – to offer a close fit that doesn't feel at all restrictive or uncomfortable whether you're sitting upright or down on the drops.

2021 Castelli Alpha RoS 2 Jacket Mens - inside panel joined.jpg

I've been using this jacket in all kinds of winter conditions, and it has put in an exceptional performance throughout. Castelli says the Alpha RoS has a temperature range of -5°C to 10°C. The coldest I went in this jacket was -2°C, but it was a really blowy day and the wind chill meant it was considerably colder, so I'd say Castelli is about right. Of course, you can always vary what you wear underneath according to the temperature too.

2021 Castelli Alpha RoS 2 Jacket Mens - zip flap.jpg

Castelli has made changes to the pockets on the latest version of the Alpha RoS. The small pocket at the front of the hip has been moved to the side panel which means you can put a little more inside without it becoming annoying when you pedal. Keys and money are fine in there although I must say that the waterproof zip hasn't been the most eager to open and close. It has been a bit of a struggle on occasion.

2021 Castelli Alpha RoS 2 Jacket Mens - side pocket.jpg

A bottom panel has been added to the rear pockets so there's now more volume inside. I didn't really notice in use because I tend to travel light anyway, but the extra capacity is there if you need it. The pockets still have laser-cut drainage holes in the bottom to stop water that rolls down your back accumulating in there.

2021 Castelli Alpha RoS 2 Jacket Mens - pockets.jpg

Of course, £290 is a lot to spend on a cycling jacket, although the Assos Mille GT Winter Jacket Evo we reviewed recently was £225 and Rapha's Classic Winter Gore-Tex Jacket is £270.

What I would say, though, is that the Alpha RoS 2's double-layer construction makes it incredibly versatile so you're getting more for your money than you might think. Plus, anything that makes riding in cold weather more comfortable has to be worthy of consideration. As long as you don't come off and rip it, this jacket will last you several years.

> Buyer’s Guide: 32 of the best waterproof cycling jackets

Overall, the Alpha RoS is a great design. The premium-quality fabrics and double-layer construction mean you can stay comfortable across a range of winter temperatures – even freezing and below – without getting too sweaty when you hit the climbs. It'll keep you dry through showers too, meaning that you don't need to mess around with a waterproof shell unless you encounter heavy rain. The all-round performance really is something special.


Exceptionally versatile winter windproof jacket that's warm and highly water resistant test report

Make and model: Castelli Alpha RoS 2 Jacket Mens

Size tested: Large

Tell us what the jacket is for and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Castelli calls the Alpha RoS 2: "[Our] ultimate jacket, bringing warmth, breathability and a high level of rain protection along with a soft, comfortable fit. With a fresh update in its third generation, this jacket leads the way in demonstrating how a winter jacket should perform."

If you'd like more detail, Castelli offers a huge writeup.

"This jacket is exactly what we think the perfect winter jacket should be. We started with a list of things we didn't like about the current jackets and set out to solve them''and in the process make our best jacket ever.

"The first issue to resolve related to moisture management. Even the best of the currently available fabrics provide a good level of breathability but can't keep up with the sweat generated during high-intensity riding. So we invented a double-layer construction that allows you to open an outer wind-protection layer while keeping the insulation layer closed and thereby allowing airflow inside the jacket to evacuate moisture while avoiding direct contact with the skin.

"On a long climb we'll completely open the outer layer to allow moisture to escape, and when we start the descent we close the outer layer and are completely dry inside. It works so well that sometimes it feels like magic. New for this year is a softer, warmer 3D insulation-layer fabric that provides better warmth, moisture management and fit.

"Next we focused on the openings: neck, waist and, most of all, wrists. The neck comes up high and is shaped to move with you, whether you're standing or in an aero position being a January hero and attacking your mates.

"For the waist we've created a stretch layer with a silicone bead that lies flat and completely seals out wind without bunching or riding up.

"New for this year is a brand-new double-layer wrist opening with an inner layer to go under your glove that seals tight to your wrist, and an outer layer that goes over your glove so that any rain will roll down the outside of the glove and not end up inside.

"Of course, the ultimate jacket will also hold up well in wet conditions, so we used Gore-Tex Infinium WIndstopper fabric along with waterproof seam taping on critical seams around the shoulder. Other seams are hidden out of direct water flow, and the water-repellent treatment on the fabric is sufficient to prevent most moisture from entering. We call it essentially waterproof, using our own subjective judgment to find a balance between water protection, breathability and comfort. It doesn't mean that no drop will ever come in, but we do longish rides in real rain and stay completely dry.

"All these features make it a favourite of the Team Ineos riders, and the most versatile performance jacket for cold-weather training we've ever created."

Castelli lists these features:

Rain or Shine engineering makes this our best jacket ever for dry conditions while also providing significant rain protection

Gore-Tex Infinium Windstopper 150 fabric for wind protection with high breathability and effective rain protection

Reduced seaming with seam sealing on shoulders reduces chances for water to enter through stitching

Double-layer Alpha construction separates insulating layer from wind/water barrier to let you better regulate ventilation

Water-resistant YKK Vislon zipper slides easily for better regulation of airflow

Raw-edge waist with silicone gripper lies flat and seals out wind

Double-layer cuff integrates with glove to prevent cold wind or water from entering at wrist

Stretch fabrics with advanced patterning make for excellent close-to-body fit that still accommodates a wide range of body types

Back ventilation

3 rear pockets with reflective laser-cut drain holes

Zippered secure side pocket for valuables

-5°-10 °C / 23°-50°F

Tell us some more about the technical aspects of the jacket?

Gore-Tex says that its Infinium Windstopper garments are totally windproof, water-resistant, and very breathable, and the performance bears that out.

Gore-Tex says, "Created using an ultra-thin protective layer laminated to a lightweight textile, Gore-Tex Infinium Windstopper products are totally windproof. Although textiles such as microfibers, closely woven fabrics and many fleece materials are often termed windproof, even light winds can penetrate most of these fabrics, making you feel chilled and uncomfortable.

"By Gore's standards, a fabric can only be considered truly windproof if its air permeability is 1.0 cfm (< 5 l/m2/s) or less. It's a standard that our products easily meet.

"The membrane technology in Gore-Tex Infinium Windstopper products has billions of pores that are 900 times larger than water vapour molecules, so even though wind can't get in, moisture from sweat vapour can easily get out.

"In addition to the GORE membrane technology, a durable water repellent (DWR) treatment is applied to most of these products. This penetrates a jacket's outer fibres, lowering the surface tension so that water beads up and rolls off. That means less water accumulation, resulting in less wind chill, and less extra weight."

Rate the jacket for quality of construction:

It's a clever construction, especially at the front where the double-layer design gives you different options to suit the conditions, terrain, and your riding tempo.

The new double-layer cuff design is smart too, stopping water from the sleeves going into the top of your gloves.

Rate the jacket for performance:

It puts in an exceptional performance across a range of winter conditions.

Rate the jacket for durability:

The fabrics have proved to be pretty hardwearing so far. I have a previous version of this jacket from a couple of years ago and that one is still looking good too, including the zip which is good news because it's a big problem if that goes.

Rate the jacket for waterproofing based on the manufacturer's rating:

Windstopper fabrics aren't intended to be fully waterproof. Rain can get inside this jacket eventually – you still need to carry a waterproof jacket if full-on rain is forecast – but water from spray and short showers beads up and rolls away.

Rate the jacket for breathability based on the manufacturer's rating:

The Windstopper fabric isn't as breathable as a non-membrane fabric, obviously, but it is impressively breathable for a windproof fabric.

Rate the jacket for fit:

I found the fit to be excellent – slim with enough stretch to prevent any rucks or ripples.

Rate the jacket for sizing:

As described on Castelli's size chart.

Rate the jacket for weight:

The double-layer construction adds a little weight, but I'm not looking to save grams in a winter jacket, I just want it to keep me comfortable in various conditions.

Rate the jacket for comfort:

I've found it comfortable in a variety of different conditions.

Rate the jacket for value:

This is one of the higher-priced winter jackets we've reviewed, but the fabric tech, the construction, and the performance are all exceptional.

How easy is the jacket to care for? How did it respond to being washed?

You wash it in the machine at 30° and it comes out fine.

Tell us how the jacket performed overall when used for its designed purpose

Exceptionally well across a range of winter temperatures; it copes with showers well too.

Tell us what you particularly liked about the jacket

The versatility of the double-layer front, and the performance of the Windstopper fabric.

Tell us what you particularly disliked about the jacket

It's definitely worth the money, but paying this amount on a cycling jacket still hurts.

How does the price compare to that of similar products in the market including ones recently tested on

The Assos Mille GT Winter Jacket Evo we reviewed recently was £225, and Rapha's Classic Winter Gore-Tex Jacket is £270.

Did you enjoy using the jacket? Yes

Would you consider buying the jacket? Yes

Would you recommend the jacket to a friend? Yes

Use this box to explain your overall score

The performance is exceptionally good, and that's definitely worth paying for if you ride year-round whatever the conditions.

Overall rating: 9/10

About the tester

Age: 48  Height: 190cm  Weight: 80kg

I usually ride:   My best bike is:

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Expert

I regularly do the following types of riding: commuting, club rides, sportives, general fitness riding,

Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.

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daflj | 3 years ago

I've got a Gabba and a Perfetto and I've never really been sure where the Alpha really sits - is it a replacement for both? Or does it sit between the two? 

No repair service also puts me off the idea of splashing that much money. Perhaps I'll have a look to see if Galibier does something similar  1

Yorky-M replied to daflj | 3 years ago

They do , have a look at the new Mistral Pro. Love mine but too warm for over 10 degrees, so would hold off until next winter

TheBillder replied to Yorky-M | 3 years ago

And Galibier also offer free repairs for a year. I asked them for help with a much older jacket that I'd bought on eBay and then crashed in, and they were very helpful in pointing me to the right patch and technique for mending it. Top kit at low prices and excellent after sales service.

bendertherobot replied to daflj | 3 years ago
1 like

Neither. It sits above them. It's a "full on winter jacket."

But, there is an Alpha ROS light jacket. That is more stripped down, does without the fleecey bits and is good, Castelli say, for 7-15c.

That jacket is similar to the Perfetto for intended use. More water resistant though.

That said, add a winter base layer to an Alpha light and you can get down below freezing in my view. My Alpha light plus Rapha winter base is very good indeed.

daflj replied to bendertherobot | 3 years ago
1 like

Thanks BTR - for £200+ notes perhaps I'll just put a thick baselayer under my Gabba then - or get the Mistral from Galibier  1

Diesel Engine replied to bendertherobot | 3 years ago

I have the perfetto and the alpha ros.  The alpha ros is a lot warmer than the perfetto, needing only a thin base layer at 0 to 5 degrees and too hot for anything over 5 degrees if putting any effort in.  Good for long rides at low intensity and low temps, but perfetto is better for most non-subzero conditions combined with a warmer base layer.

Rapha Nadal | 3 years ago

I have the first edition of this jacket and it is indeed fantastic.  Ridiculous levels of warmth in the depths of winter!

However, Castelli really let themsleves down with their lack of backup service.  Came off on ice last winter and put a hole in it but Castelli won't look to repair it which is appalling for a jacket costing nearly 300 notes.

Yorky-M replied to Rapha Nadal | 3 years ago

How is it Castelli's fault you came off on the ice? Thats your fault! That like crashing your Fiesta and calling Ford to complain. World is full of blame shifters. There are Zip yards in every town.

Rapha Nadal replied to Yorky-M | 3 years ago

Where did I say it was Castelli's fault?  I''l wait whilst you point that bit out to me.

If you care to actually improve your reading skills then you'd note that my issue is with Castelli's lack of aftercare for those "oops" moments.  if Rapha and Assos can offer it then there's no reason why Castelli can't.

In addition, how many Zip Yards do you know that carry Gore Tex Infinium?  None?  Thought so.  Dickhead. 

Bookwyrm replied to Rapha Nadal | 3 years ago

I've had really good success with using GoreTex repair patches on my Perfetto. They have lasted over a year since being put on and mean the jacket was not a write off.

Rapha Nadal replied to Bookwyrm | 3 years ago

I too was looking at those after a friend had a similar success to yours.

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