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Castelli Alpha Ros Long-Sleeve Jersey - Men's

Item # CST00IN

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Item # CST00IN


Next Level Jersey.

The Castelli Alpha ROS Jersey is more than meets the eye and it strives to be your go-to winter jersey this season. It's almost a hybrid between a jacket and a jersey and like most of cuts of Castelli's clothes, it has a slim, next to body fit. What makes this jersey really unique is the double layer front for maximum temperature regulation with each piece having its own zipper. The Windstopper material and seam sealing echoes a similar design ethos of the Alpha ROS jacket, but is suited for temps that are a little warmer.

ROS stands for Rain or Shine and Castelli uses that acronym on their premium products offering protection in cooler weather, both wet and dry. The ROS pieces are designed to perform better in the wet and wind than your typical thermal piece and give you more warmth than a rain cape. If it's a deluge of heavy prolonged rain, you might want something a little more impermeable, but if it is damp, misty conditions that we so often see in spring and fall, or on and off showers and wind, this is where the ROS is designed to excel.

The Alpha ROS Jersey improves upon last year's jersey with all new fabrics which greatly increase its water repellency and a reduction in seams enhancing its resistance to rain. We also see new waterproof zippers, laser cut drain holes on the rear pockets, and a raw edge waist. The Nano Flex Xtra Dry back offers the most significant non-membrane water protection available and exceptional breathing. It might not keep every drop of rain out but it will leave you as comfortable, warm, and as dry as possible in more situations than any other garment.

  • A race-cut, weather-resistant cycling jersey
  • GORE Windstopper 150 is breathable, all-weather protection
  • Racing fit is cut to eliminate flapping material
  • 2 layer front design dumps heat during hard efforts
  • Laser-cut mesh drains in the three rear pockets
  • Reflective accents adds visibility in inclement conditions
  • Castelli redefine all-weather racing kit

Tech Specs

[membrane/laminate] Windstopper 150 (front and sleeves), [face fabric] Nano Flex Xtra Dry (back), [liner] ProSecco Strada
spring, fall
[front] 1 zip, [rear] 3
rear pockets
Recommended Use:
road cycling
Manufacturer Warranty:
1 year

Size Chart


Men's Apparel
Chest 36.2in
Waist 31.5in
Hip 37in
Inseam 31.9in
How to Measure:
For best results, take measurements over your underwear.
Measure under your arms, around the fullest part of your chest.
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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Warm even in pretty cold weather

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

I wore this today with the outside temperature at 35 degrees. I did not wear a base layer and it was great. The wind stopping technology was amazing. Once I got up to warmth I was very comfortable. Once again with any Castelli go up a size if your American.

I have last season's Alpha FZ wind jersey. On that piece, the internal lining only covers the front torso and back torso while the sides, shoulders and arms are plain un-insulated windstopper fabric (much like a "perfetto" piece). It's still a great jersey but this omission just means it's not quite as warm as it could be. Does this new ROS jersey have insulation down the sides, shoulders and arms or is it much the same as the older Alpha FZ?

From what I can see, it's just the vest area. Torso only; no arms. With tops like this, I always prefer flexibility, anyway, so I opt for the shell and baselayer approach. And frankly, at this pricepoint, I think the eVent membranes on Giordana's AV gear are better options. They breathe far better because they don't require the presence of moisture before they start breathing. (This is coming from someone whose winter cycling setup is a merino base layer and a Gabba jersey. The eVent membrane on Giordana's AV stuff is just better.)

Fantastic piece

  • Familiarity: I've used it several times

My first test has taken this on a brisk 48 degree day. I climbed up Big Cottonwood Canyon gaining about 2000ft elevation gain before plummeting back down. The Windstopper did what it is supposed to do. Stop the wind. I think this jersey will have a range of appropriate temperatures depending on baselayer used. I could see that being in the 40-55 range most comfortably. I really liked the cuffs on the sleeves- perfect for tucking in or putting over gloves- depending on which gloves you have.

My favorite feature was the built in ‘vest/inner liner’- This was perfect as the climb up I was heating up quick and opened the outer layer up. Zipped it back up at the turnaround and let the Windstopper do its thing on the descent. 5’11 175lbs the large fits great.

Hey Scott, I've posted a question in the Q&A section - if you have a moment, would appreciate your insight into the extent/coverage of the insulation. Cheers!