The Secret Weapon: Castelli’s Claudio Bib Shorts

Some years back I came across a set of bib shorts made from Roubaix Lycra. Back then, Giordana was the only company I knew was producing such a garment. Before I encountered them I thought that Roubaix Lycra was strictly the province of arm, leg and knee warmers, tights and knickers. It would be a few years before I saw long-sleeve skinsuits made of the stuff for ‘cross racers.

My introduction to them was accompanied by the same exuberant Aha! I experienced when someone first showed me Tegaderm. It was a product utterly useless for most of the year, but when you needed it, nothing else would do, and I knew when you wanted such a device.

Bibs such as these were intended for days that get described as atrocious, nasty and epic. These bibs are what you pair with embrocations of such heat that a shower eight hours after application is still uncomfortable. In short, if you need an embro marked “nuclear,” then you deserve shorts made from something that offers greater insulation than 8-ounce Lycra can.

What became of that first pair I encountered, I don’t know. One winter day I went digging in a box of seldom-used winter stuff and they had vaporized. I missed them the way you miss certain heavy metal albums: almost never, but occasionally, nothing else suits the mood (or conditions).

At Interbike I learned about the Castelli Claudio bib shorts. These are one of a handful of thermal bibs on the market; naturally, Assos does a pair as well. They are cut from Castelli’s Nanoflex fabric, which is used in the company’s best tights, knickers and warmers. Nanoflex is a thermal Lycra coasted with tiny (nano—get it?) silicone fibers that makes the fabric unusually water repellant. I didn’t appreciate just how water repellant it was until I saw some water dumped on the material when it was cupped in someone’s hand and the water just rolled around on the fabric without soaking in. You could say that Nanoflex is Roubaix Lycra for the 21st century.

The bibs are cut from a polyester mesh so that your torso doesn’t get overheated and moisture is wicked away quickly. These bibs are equipped with Castelli’s KISS3 pad, which, while not the company’s top-of-the-line pad is honestly better than most companies’ best pads. The leg grippers are industry-standard silicone ones that are completely ineffective on a properly embro’d leg, not that I mind.

I log the vast majority of my winter miles in the morning when there’s not a lot of light. Even so, I don’t usually tend to get too excited about reflective accents, but I do think it was pretty bright to make the reflective spots on the back of the bibs actual tags that protrude from seams on the hips so they can be seen from more angles than just directly behind the rider.

I used to pull out the set of thermal bibs I had any time conditions turned both cold and wet. I’m not a fan of soaked knee warmers, Philippe Gilbert at Lombardy notwithstanding. I referred to the combination of those bibs with a hot embrocation as the secret weapon.

It would be easy to reject special-purpose bibs if they ran $300. The Claudio bibs are only $129, affordable enough to be worth adding to your winter wardrobe.

While I haven’t had a chance to try these bibs in truly cold temperatures, I frequently used my previous set down into the 40s. Castelli says these are appropriate for temps between 50 and 64 degrees, but I suspect you’ll find them handy in even cooler conditions.

We all need a secret weapon. Staying comfortable is mine.

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  1. matt

    tis the season indeed. im looking for a set of bib kinckers. oddly i am looking for them the same day this popped into my rss feeder. how would you say this compares to the casetlli fondo bib knickers?

  2. bwebel

    Must be nice riding in SoCal. Shorts like these are about all I wear from now till March or so, they are nice under tights as well. Lots of companies make them; Pearl, Craft, and Descente come to mind off the top of my head. The previous models of Pearl had a lot of reflective stuff on them, I tend to pull them out for the dark morning commutes.

  3. michael

    Rapha makes a mean pair of thermal bib knickers. Their cross version is a little bit lighter weight but still very effectively insulated. Love the chammy in this model as well too, nice fleece-like covering to keep your bits warm (at least the 2009 version I own, i haven’t seen the 2010 model yet). So long as you can live with the envious looks and snooty taunts from sarcastic cyclists you are golden.

    Sugoi make a good thermal bib knicker as well, the RS Zero (in the interests of full disclosure I happen to work for Sugoi). One potential drawback to these is the lack of any gripper material at the bottom of the leg. If you are skinny legged like me this causes the bottom part of the leg to bunch up behind the knee. Those of you with beefier calves won’t have this issue.

    Assos make the best thermal bib knickers out there, at a premium of course but you get what you pay for – incomparable fit and luxurious feel mated to outstanding performance.

    Not a personal fan of the Pearl model, it just never worked for me but personal fit is such a subjective thing.

    Craft make a good budget-conscious option that is decent quality for the dosh.

    Have never owned anything Descente so can’t comment on their. Garneau make a nice one as well too, the fit is great but their chammy’s have never worked very well for me.

    It is surprising how few companies offer well designed and built thermal bib knickers.

    1. Author

      Big E: Tegaderm is a clear bandage that does wonders for road rash. May warrant a separate post.

      Bwebel: It’s nice that the number of companies offering thermal bibs has increased, but I’m amazed that even with the new additions (Pearl and Descente are very recent entries) this item isn’t standard in everyone’s line.

      Michael: I’ve taken some heat here for reviewing so many pricey items. I selected the Castellis because the material is so miraculous and they go for less than folks might expect. Assos deserves noting here as their thermal bibs only go for $169.

      As to bib knickers, these are problematic. Most only come to just below the knee and I generally feel like if I’m going to have that much thermal material on my body, I want it to cover my calves as well. I have a set of Assos thermal bib knickers that I purchased more than a dozen years ago and they are pretty extraordinary. I tend to head for knee warmers just so I can keep my calves covered.

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  5. Lachlan

    I’ve both Assos and Rapha bib knickers – and while both brands do amazing shorts, intergral knickers seem always to be less comfy.

    Give me shorts+ good knee warmers (like the Rapha ones) anyday! So much more comfortable and flexible of course!

  6. number1dane

    Great review, Im out to get these bibs! Could you perhaps tell us about the sizing? Castelli seems to run small. Which size did you get and how do they fit to your ‘size’.

    1. Author

      Number1Dane: Sizing does run a bit small with all Castelli stuff. I’m a medium in almost every bib on the planet (we won’t go into Assos), but I’m large in both Castelli and Panache.

  7. matt


    I second the comment of padraig on fit. I usually fit pretty comfortably into large shorts, some brands I’ll wear a medium sized jersey. I found the of these Castelli Claudio shorts locally and tried them on. I fit into an extra large! for reference I am 6 foot 2 inches and have a fighting weight of 180.

    thanks for the recommend padraig, these shorts are shaping up to be some winners. might have to pair them with the nano flex knee warmers for wet pac nw winter riding

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  9. [email protected]

    I don’t know how Matt (above) fit into a pair of XL’s at 6-2, 180#. I’m about the exact same size and I’m wearing the XXXLs! Yeah, that’s 3XL. I usually wear an XL. Consider, too, that you’ll be wearing a wool base layer under the bibs and will probably have leg/knee warmers tucked under the upper leg material, so a bit bigger works OK.

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