Castelli Insolito Radiation Jacket

By STEPHEN REGENOLD

In the hype of a press release, Castelli touts its latest three-season cycling jacket as a “breakthrough technology that ushers in a new era of comfort and performance.” With a stretchy, fluorescent-yellow face fabric, zip-off sleeves, vents, and a liner of metalized polyester, the $499 Insolito Radiation jacket does indeed stand out as something new.

Extreme adaptability to outside temperatures during the autumn, winter and spring cycling seasons is the Insolito’s primary claim to fame. With a modular design, wearers can pull on a hood, open vents, add a liner, or zip off sleeves to create a vest. These regulating attributes result in a piece the company cites as having a comfort range for cyclists from 25 to 65 degrees Fahrenheit.

The modular nature of this piece is nothing new. Outerwear makers have long sold ski jackets and other pieces with removable components to regulate heat. But what makes the Castelli concept unique is a fabric technology in the liner that uses a thin reflective material akin to Mylar and other similar metalized “space blanket” materials. Called Radiation fabric, this silvery sheen helps maintain body heat without relying on a bulky insulation like fleece.

I got a press sample of the Insolito in August and rode with it during a couple cool September nights. This was not the optimal — nor intended — time of year for the piece, but even so I could feel the Radiation fabric doing its thing. Like a space blanket, the liner reflected and retained body heat that would otherwise ostensibly be escaping into the ether. (Castelli purports that 80 percent of the body’s heat is reflected back with the aluminum-based liner.)

To keep the jacket breathable, Castelli (www.castelli-us.com) perforates the metalized film and laminates it to a woven substrate. The final product, in the test size large, is a crinkly wisp that weighs 3.9 ounces on my scale.

The jacket’s outer shell is made with Gore’s Windstopper X-Lite fabric to shield from cold blasts seeping through the fabric face. Though it’s not made for rainy rides, the water-resistant Insolito will protect against snow, sleet, ice and other wintery elements that might fall from the sky.

Overall, the Insolito got my attention for its new approach to heat regulation. My tests this winter, riding through the Minnesota snow in temps well under freezing, will result in a final verdict.

The jacket, which comes in red and the highway-worker yellow, is a high-quality piece, well-fitting and with all its pockets, zippers and vents in the right places. The cut is long at the back, short at the front, with jersey pockets all around. Its stretchy, fleecy hood is tight and warm, and it fits under a helmet without issue.

The Radiation liner zips in and out from the Windstopper shell. You add it to the setup on the coldest days. Small snaps secure the Radiation liner’s sleeves and hold the top in place.

At its retail price of $499, the Insolito Radiation jacket and its cousin, the women’s Alamos, do not have mass market appeal. But for the cyclist who wants an all-in-one system — or something with the utmost in versatility — this shell with a silvery sheen inside could be a perfect fit for the cold-weather pelaton.

(Stephen Regenold writes The Gear Junkie column for eleven U.S. newspapers; see www.THEGEARJUNKIE.com for video gear reviews, a daily blog, and an archive of Regenold’s work.)