Castelli Alpha RoS Cycling Jacket

Anyone who rides road bikes seriously knows Castelli! The Italian brand with the scorpion logo has been developing and producing top-tier cycling apparel for decades. Castelli is clearly a trendsetter in both technology and style, always a step ahead of the competition. We’d like to introduce you to the innovative “Rain or Shine” (RoS) concept and Castelli’s “Alpha” jacket construction so that you’re perfectly equipped for the coming autumn and winter season.

The secret of Castelli’s Alpha jackets

Almost every road cyclist has a classic softshell jacket for the cold season hanging in the wardrobe. A 3-layer softshell consists of a water-repellent outer, a windproof membrane, and a warming fine-fleece inner.

This was the challenge that Castelli ultimately solved with the Alpha jacket construction. The result is as simple as it is ingenious. Castelli decoupled the layers: while the membrane is breathable so that excess body heat can escape, many softshells struggle to evacuate the sweat produced under high exertion. On a long, steep climb, a classic softshell often can’t keep up with the moisture load. You’d have to open the jacket and risk getting chilled.

1. The top first layer is a thin Gore-Tex Infinium Windstopper 150 membrane fabric. It is completely windproof, extremely breathable, and highly water-repellent.
   
   
2. Underneath, as a loose second layer, a warming vest is integrated in the wind-facing area, and on the back a loose, quick-drying mesh lining is used.

When you start to sweat on the climb, you only open the thin outer windproof layer. The insulating vest stays closed so your core doesn’t cool down. Airflow between the layers dries the transported sweat. For the descent, you close the outer layer again—your body stays dry and warm.

Of course, you can also fine-tune temperature by opening the vest itself.

The Alpha RoS winter jacket has become a hit among ambitious cyclists despite its relatively high price—because it offers many other technical advantages:

• low-seam RoS construction with taped/welded shoulder seams to keep rain out,
• a close-to-body fit that, thanks to the fabric’s elasticity, suits many body shapes,
• a waterproof YKK front zipper,
• a wide stretch hem with flat laser-cut finish and inner silicone prints that seals out cold air,
• an ergonomic, high stand-up collar that adapts to your position—whether you’re tucked on the drops or climbing out of the saddle,
• double-layer cuffs that integrate perfectly with gloves,
• hidden rear ventilation openings for optimized breathability,
• three spacious rear pockets with laser-cut drain holes for rainwater,
• a zippered valuables pocket,
• designed for temperatures around the freezing point
  
  

The winter jacket was practically the prototype of the Alpha line. It was followed by an entire family of jackets, light jackets, and long-sleeve jerseys using the Alpha 2-layer construction. By varying insulation levels and the placement of Gore-Tex Infinium, there’s a wide range of applications for every season.

As an example, we’d like to highlight the Light Jacket Alpha RoS:

• Layer 1 (Gore-Tex Infinium Windstopper) covers the front and the pockets as a spray guard; the back is left free,
• the integrated vest made of lightweight polyester is not primarily for insulation but for moisture management,
• the back uses a warming winter polyester with fine-fleece inner and a water-repellent nano finish—more breathable but with less wind/weather protection.
  
  

The jacket is therefore less insulating, but more breathable and lighter—ideal for the transitional seasons.

And by the way: the Alpha jackets are, of course, available for both men and women!

RoS (Rain or Shine) – Castelli’s all-weather concept

Especially for road cyclists, carrying a backpack on a day ride is unpopular. The apparel simply has to withstand changing weather. In-between seasons and in winter the challenge is to stay dry from the outside and inside, without chilling or overheating. Layering with baselayer, jersey, gilet, rain jacket, arm/leg warmers, etc. is possible—but it fills rear pockets (that you’d rather use for bars) and requires constant changes. Castelli’s RoS (Rain or Shine) approach is gear that works in both rain and sunshine—less changing, fewer overstuffed pockets.

As you might guess, the Alpha construction—and especially the new Gore-Tex Infinium Windstopper fabric—plays a key role here.

This innovative material doesn’t just block cold wind. Compared to conventional membrane fabrics, it offers:

• extremely high breathability to quickly move excess heat outward,
• very high water resistance—while not 100% waterproof like classic Gore-Tex, it’s sufficient for a day ride in changeable weather,
• very fast drying,
• and excellent elasticity for a truly close, body-hugging fit.
  
  

For RoS apparel, Castelli uses Gore-Tex Infinium Windstopper in low-seam patterning to prevent leakage through stitch lines. Exposed seams are taped or welded so water can’t penetrate. You’ll find RoS in these Castelli families:

• Alpha winter jackets and light jackets
• Perfetto jackets, Perfetto light jackets, and Perfetto vests
• various winter gloves, caps, and overshoes

Conclusion:

In short, we can highly recommend the Alpha RoS winter jacket. It combines the benefits of the decoupled-layer concept with Gore-Tex Infinium Windstopper and a low-seam, water-resistant build. With Alpha RoS you can regulate core temperature under heavy exertion, saving energy and focus for your ride. A worthwhile investment!

P.S.: If you have further questions, leave us a comment or send us an email. We’re happy to help!