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Alpha RoS 2 Jacket - Men's

4.538461538461538 out of 5 stars
26 Reviews

Out of Stock

Don't worry though, we have a lot more Men's Bike Jackets & Vests in stock than that.

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Why We Like The Alpha RoS 2 Jacket

For those of us who have not been swooned by months of indoor training during winter, Castelli’s new Alpha RoS 2 Jacket provides a feature-heavy barrier against nature’s bite, ensuring the miles are logged even in the harshest conditions. Continuing Castelli’s impeccable lineage of inclement weather, performance clothing, the Alpha RoS 2 gets a double-layered Alpha construction comprising an inner insulation layer and outer GORE-TEX INFINIUM wind and water barrier. The layers provide protection down to 23 degrees F as well as superior wind and water resistance to brace against pocket showers or a ride-long drencher.


  • Winter-ready cycling jacket faces the elements in comfort and style
  • Double layer Alpha construction insulates and shields from nature’s bite
  • Gore-Tex wind and water barrier also provide stretch in riding position
  • Water-resistant zipper and double-layer cuff discourage water entry
  • Upper-back venting channels manage heat buildup while training
  • Reflect drain holes on pockets won’t slow you down
  • Rated from 23-50 degrees F
  • Item #CSTZ7D0
Double Layer Alpha, [inner] insulating, [outer] GORE-TEX INFINIUM WINDSTOPPER 150
waist with drop tail
Center Back Length
[medium] 27in
[back] venting channels
3 rear, 1 zippered
[pockets] laser-cut drainage holes
Claimed Weight
[large] 1lb 2.5oz
Manufacturer Warranty
1 year

Overall Rating

4.5 based on 26 ratings

Review Summary

1 Stars - 1 reviews
2 Stars - 1 reviews
3 Stars - 2 reviews
4 Stars - 1 reviews
5 Stars - 21 reviews

Fits Small

Screen reader users: the following list provides a visual scale to illustrate the product fit. Please refer to the heading above for the fit type in text.
Runs smallTrue to sizeRuns large

What do you think about this product?


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5 out of 5 stars

March 4, 2023

Best Jacket Ever!

I've used it several times

I can't say enough about this jacket. The level of design put into this jacket is amazing between the multiple layers of material, internal wrist cuffs with overlapping shell, raised collar, etc. I've worn this jacket between 20F on the trails to 45F on the road and it's covered the full range. The wind and waterproof shell keeps the cold air and water off you while the multiple layers allow your body to breath and shed excess heat. Makes a great pair with the Castelli Roubaix thermal base layer. The fit is VERY snug and definitely cut for the trim cyclist. At 6' and 165, the large fits me like it was tailor made to my body.

Chris R

Originally reviewed on

5 out of 5 stars

December 24, 2022

Nice jacket, runs small

I've used it once or twice and have initial impressions

Worked well for me with a lightweight underlayer in 40 deg F weather. Should work well in colder temps with a thicker underlayer. Fit is Euro-snug. I'm 5'8" / 148lbs and Large is about right.

bam98772073224 b

Originally reviewed on

5 out of 5 stars

April 19, 2022

Excellent jacket; size runs way small

I returned this product before using it

I have a 38-39" chest, normally a medium with my other clothes. But having read that the jacket runs small, I ordered a size up. The large was still too small, but they didn't have an XXL. The return was quick & easy. Instead, I got the jacket in the Light version (3-season instead of winter only) in XXL and it fits perfectly!

Lonnie M

Originally reviewed on

2 out of 5 stars

March 28, 2022

great, but incredibly fragile

I've put it through the wringer

The fabric and fit are perfect; I've had it about a month and it's kept me warm in rides at around 20 degrees fahrenheit. But the middle rear pocket is already unravelling, though I've used it only for carrying a small Lezyne pump and a cell phone. I'm afraid this is a trend in Castelli items I've ordered recently: perfect fit, great design, amazing fabrics, but constructed so shoddily that they don't last nearly long enough to warrant their price.


Originally reviewed on

4 out of 5 stars

January 30, 2022

Careful when sizing up

I returned this product before using it

I read the reviews and sized up as recommended for my build&purchased the XL. The sleeves are too long and the neck is large as well. This jacket is not form fitting for my regular body type. I will try again in a size L. Update: the size L was a perfect fit. Initial ride, wearing a merino wool base layer for 2hrs @ 32F, was successful. Will give it a full review after more rides.

Paul C

Originally reviewed on

5 out of 5 stars

January 27, 2022

Great addition to winter gear!

I've used it several times

I have been looking for a well priced winter jacket that is warm and blocks wind. I found it! Used it on 2 rides to date in 30-40F with a warm (winter) base layer only. Coolish to start but warmed up quick with good ventilation and no condensation. Above 50F and moderate riding it is too much jacket unless you unzip it...perfect for Colorado winters! I'm usually a large in most jackets, but this runs small.

Scott R

Originally reviewed on

5 out of 5 stars

January 26, 2022

Great piece of winter kit

I've used it several times

I recently purchased a RoS 2 jacket to replace an aging Castelli Espresso winter jacket. So far so good, I have had 3 rides in it while we are trapped in a foggy inversion, temps have ranged from 0-4 Celsius (32-39 F) and I been toasty warm wearing only a Craft Active Extreme short-sleeve base layer. With a LS baselayer I fully expect I could be riding down to -5 C on the road no problem, but I also think above 6 C (42 F) this jacket might be too much. In terms of size, I am 6' tall and 170 lbs, with a 38 in chest and 33.5 in waist. I do not have big shoulders or bulky arms, my arm length is probably a tiny bit longer than average. Size L is perfect for me, allows just enough room for base layering, perfect sleeve and body length. I was tempted to size up, but stuck with my traditional Castelli sizing. The only niggles I would have with this piece are very minor. It would be awesome if the zipper was a 2-way zip so it could be undone from the bottom up for ventilation purposes, but I also get that those zippers tend to be a little less reliable. The rear pockets are good sized, but the Gore Infinium does not have a lot of stretch so loading up the pockets feels snug. This is a good thing for keeping things in place, but just a tiny bit more stretch and/or volume would be better. Still, neither of these niggles are worth knocking off a star, as this jacket is pretty much perfect.


Originally reviewed on

5 out of 5 stars

January 25, 2022

Expensive but I love it!

I've put it through the wringer

I struggled about paying this much for a jacket, but I am happy that I did. I have done quite a bit of winter biking over the years and this jacket is by far the best I have ever used in the cold.

United U

Originally reviewed on

5 out of 5 stars

January 3, 2022

Perfection without regrets

I've put it through the wringer

As my deep winter jacket gave its last full measure, I needed a stellar replacement and have found it in the Castelli Alpha RoS 2. Having had awesome experiences with the Castelli Alpha RoS Light jacket, I hoped that the bigger sibling would deliver in the below freezing morning darkness. Wow, even with the "Light" experience, I wasn't overly confident that upper teens to low twenties would be a happy place. Seriously; this jacket ROCKS. Vary the base layer and I have a tool that picks up at 44F where "Light" drops out. Have explored very heavy to summer sleeveless base layers, two layers (base and Alpha) as the right stuff. Just as happy spinning the wind and weather at 45F as I am at 25F! Love how the cuffs integrate with gloves, over, under or middle! Don't pass Go, don't collect&just buy it already, with zero regrets! For sizing, I am 6'1'' / 175 lbs and am really happy with XL for both Alpha RoS versions. May have to become a RoS fanboy, as this my third Castelli RoS piece (Perfetto Light gloves as well) and the perfection is amazing

Brian B

Originally reviewed on

5 out of 5 stars

December 21, 2021

Expensive but works

I've put it through the wringer

With arm warmers and/or a base layer, this jacket works well for me for road cycling into the mid 20s. Amazingly good at keeping out wind.

Robert M

Originally reviewed on