The Castelli Sanremo Thermosuit
The Castelli Sanremo Thermosuit

The Cyling Onsie Arrives

Laugh all you want, but the Castelli Sanremo Thermosuit one-piece might be the warmest winter cycling outfit we’ve tried

The Castelli Sanremo Thermosuit

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When I first received Castelli’s new winter offering, the Sanremo Thermosuit, I laughed out loud. Onesies might be popular for skiing, but otherwise they seem like something best reserved for the intimacy of your own home. Truth be told, I blushed thinking of how hard my riding partners would laugh when they saw me in this.

But then I tried it one day, and I haven’t ridden in anything since.

Technically speaking, the piece is a Transparente jersey fused to a Sorpasso tight. The jacket upper has panels of Gore Windstopper X-Lite on the front to stop the chill air and a stretchy, fleecy material called Thermoflex Core Due on the back that breathes well. The front zip opening is weather sealed and includes a cam-lock zipper for easy up and down. The tights are constructed from the same soft material as the rear of the jacket and built around the seamless Progetto X2 chamois, one of my favorites on the market.

In spite of my initial skepticism, I haven’t found anything nearly as practical or warm for very cold riding. The seals around the neck, wrists, and ankles, as well as the lack of opening at the waist, basically shut out the cold better than any jacket-tight combo. I have worn the suit over a mid-weight base layer on top and ridden comfortably for hours down to 18 degrees. I added only an insulated vest to the ensemble and was comfortable from there down to zero degrees. It also doubles nicely for skate skiing.

At $350, you’d have to log plenty of cold-weather miles to make the Sanremo Thermosuit pay off. However, if you spend a lot of time in the saddle in winter, as I do, it’s well worth the price. It’s definitely a piece of apparel I never knew that I needed—and one that will be a mainstay in my winter closet from here forward. As for my training partners, I imagine I’ll be the one laughing while they are shivering in envy.

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