Over the past several years, Castelli hasn't been shy about making extraordinary claims for its foul-weather kit. That's because the brand behind the iconic red scorpion logo has been making foul-weather kit extraordinary enough to live up to those claims. With the Potenza Men's Jersey, Castelli has once again reset our expectations by building a jersey/jacket thing that combines wind-resistance, thermal insulation, high breathability, and a water-resistant finish.
Those are big claims, we know, but Castelli tested them by giving the Potenza to a few professionals to try, and the brand reports that they are clamoring for race versions. There isn't currently one in the works, though, which means that—like with disc brakes and sub-15lb bikes—we consumers get access to stuff before the pros themselves.
The Potenza consists entirely of a single fabric, Polartec's Power Stretch fleece. Given Castelli's penchant for targeted constructions comprising multiple fabrics at strategic locations throughout the jersey, this relatively short ingredients list gave us pause. We found ourselves reflexively scanning the spec sheet for the inevitable "stretch inserts" that are often credited with compensating for the lack of breathability and inconsistent stretch-and-return properties of most foul-weather fabrics. We never found them because they aren't needed.
Power Stretch breathes, wicks, and stretches more like a base layer than an outer layer, but its densely woven knit and hard-face finish give it the durability and wind-resistance of a light jacket. When hit with a DWR treatment, the result is a top that blurs the gap between thermal jerseys and winter jackets by combining the breathable stretch of the former with the warmth and light elemental protection of the latter. It isn't water- or windproof, but that hard face finish does cut the winter chill and light precipitation and road spray beads up to be shaken off without penetrating.
Though Castelli doesn't call it out in its own catalogue, the Potenza is finished with full windproof protection at the throat and across the leading edge of the upper chest/shoulders, protecting an exposed area that often gets overlooked. The rest of the jersey's finishing touches exhibit a similar comfort-first ethos, including the lie-flat, bonded waistband and the CrossWrap wrist closures, which slide under gloves for plenty of protective overlap.
While layering, we find that the Potenza functions as a stand-alone layer in fall and spring or a super domestique base layer under a shell in the most violent depths of winter. When sized up, the Potenza's slim jersey fit becomes a layering jacket fit, letting you pop a thermal top underneath for dry days when you just need more warmth. Regardless of when you wear it, the Potenza is the very avatar of utility; it's finished with the erstwhile standard of three rear pockets, which is supplemented with the new standard of a fourth, zippered pocket, which is in turn updated with a zippered chest pocket. This frees up the three rear pockets for stowing thermal accessories by providing ample space for personal effects in the fourth and fifth pockets.
- Castelli's latest thermal cycling jersey revelation
- Thermal material is tightly knit to resist wind
- Breathes and stretches better than fully windproof membranes
- Additional wind protection on throat and upper chest
- Slim fit and soft finish recommend it as a mid-layer
- Low profile cuffs and bonded, lie-flat hem
- Five pockets, two of which zip closed
- Reflective details help keep you visible when the light falls