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Castelli Nano Flex 2 Bib Knickers - Men's

Item # CST00DK

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  • Black, M ($129.95)
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Item # CST00DK


Don't be afraid of rain.

Ill-fitting knickers are the bane of road cyclists' existence, particularly those who train in cold-weather locales. If you can't recall a pair of knickers you've owned that you've actually liked, know that you can toss your ill-fitting old knickers and trade them for something made to fit well. Castelli's expertise in fit is no secret, and the Italian firm takes the construction of its Nano Flex 2 Bib Knickers as seriously as the rest of its impeccably tailored kit.

Whether the skies look gloomy before you head out or you're caught in a surprise shower, Nano Flex fabric was created specifically to combat wet, inclement weather on the bike. The Nano Flex 2 Knickers continue the legacy their predecessor set, repelling water while establishing a layer of warmth close to your skin.

Castelli purposely eliminates seaming wherever possible to reduce the likelihood of water soaking through the knickers, and it adds secure Giro3 grippers to the cuffs to create a consistent fit that seals out road spray. The bib itself is mesh, airy and breathable, designed to subtly sit under a jersey and be barely noticeable when you're pedaling. Castelli's Kiss Air chamois loyally stands guard between you and the saddle, providing multi-layered cushioning that remains supportive and breathable over the miles, however cold and rainy they may be.

  • Ride comfortably through unpredictable weather
  • Fabric repels water and holds warm air next to your skin
  • Slim cut with minimal seaming moves with you on the bike
  • Lightweight, airy mesh bibs aid in breathability
  • Plush chamois ensures long-ride comfort and support

Tech Specs

Nano Flex
yes, KISS Air
Claimed Weight:
[large] 215 g
Recommended Use:
Manufacturer Warranty:
1 year

Size Chart


Men's Apparel
Chest 36.2in
Waist 31.5in
Hip 37in
Inseam 31.9in
How to Measure:
For best results, take measurements over your underwear.
Measure under your arms, around the fullest part of your chest.
Measure around your natural waistline, keeping the tape a bit loose.
Measure around the fullest part of your body at the top of your legs.
Using pants that fit well, measure the crotch seam to the bottom of the leg.

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Good quality; Sizes are off

  • Familiarity: I returned this product before using it
  • Fit: Runs small
  • Size Bought: large

I had to return these. I'm 6'3", 185 and I couldn't get a size large on. The quality of the material and craftsmanship was very very high.

does the job

  • Familiarity: I've put it through the wringer
  • Fit: True to size
  • Size Bought: large

they won't keep you dry but I've found that even in very cold and wet conditions you still have some warmth in the groin and legs. way better than wearing regular bibs with leg warmers. They do shed a lot of spay as well.

Surprised to hear that they don't keep you dry since I thought that was their function.

I have the Nanoflex bib shorts, leg warmers and arm warmers. They are not completely waterproof, but they do shed water. The real beauty of the Nanoflex fabric is that it strikes a nearly perfect balance between water resistance and breathability. The fabric is impregnated with something hydrophobic like silicone. It never gets completely saturated or water-logged but remains completely breathable. It's also fleece-lined for real warmth but is not windproof. The water resistance is diminished over time by repeated washing.