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Castelli Mens Nano Flex Pro Race Bibshort Black
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Men's Nano Flex Pro Race Bibshort

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  (4 customer reviews)
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Incredible improvement of a simple idea — clearly evident in the Castelli Nano Flex Pro Race Bibshort for Men.

A few years back, Castelli pioneered the first Omloop thermal short — inspired by pro riders cutting off their knee warmers to just the bend of the knee at the Omloop Het Nieuwsblad on a brisk sunny morning. And thus, Castelli set about making a bibshort cut right to the bend of the knee, eventually culminating to the ingenious invention of the Castelli Men's Nano Flex Pro Race Bibshort.

Constructed using the new third generation of Castlli's Nano Flex fabric to create a fit that is just as soft, stretchy, breathable and warm as the original Thermoflex fabric. Ideal for cool and dry conditions like the day it was thought up, while also excellent on wet days to turn any cyclist into a professional in a flash. And don't forget that these bicycle shorts are still a pro tool — this short is identical to the model supplied to Team Ineos.

Those first Omloop shorts were made for cool, dry conditions, like the race that inspired them. The Castelli Men's Nano Flex Pro Race Bibshort took this idea and made it great, improving the torn warmers with incredibly durable Nano Flex fabric to provide a more comfortable fit that adds just enough warmth.


  • Nano Flex 3G fabric is water repellent, stretchy and warm thanks to the luxuriously soft brushed inside
  • Reduced seams for comfort and to prevent water from coming in during wet rides
  • Knee-length cut for extra warmth that doesn't require a gripper elastic
  • Mesh bibs are lightweight for optimal layering
  • Progetto X2 Air seamless seat pad for long hours in the saddle

  • Free Exchanges: This product qualifies for free exchanges within the first 60 days after order. We'll cover the shipping both ways for US customers if you need a different size and/or color of this product. Returned product must be in new condition with all labels and packaging. Free exchanges apply only for product in stock or available for backorder.

    B-Stock - This product has one or more B-Stock units available. These units can be purchased at a discount (see option select). B-Stock units were returned from other customers and may have missing or damaged packaging materials. These units are otherwise as new. The full manufacturer warranty applies. Click Here for more information.


    Style Type: Bibs 

    Black - Small

    Mfg PartNum: L20521010-2 

    Black - Medium

    Mfg PartNum: L20521010-3 

    Black - Large

    Mfg PartNum: L20521010-4 

    Black - X-Large

    Mfg PartNum: L20521010-5 

    Black - 2X-Large

    Mfg PartNum: L20521010-6 

    Black - 3X-Large

    Mfg PartNum: L20521010-7 

    Ordered by Most Relevant First
    5 stars
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    1 stars
    Difficult to find a fit
    by  OZ

    I'm 5'9" 160#. I ordered mediums and thigh and waist were find. Pad was a good size. Shoulder straps were TOO TIGHT. Ordered large, they aren't tight above the knee, and the pad is too wide feeling like a diaper and catching on the nose of my saddle. Great kit if I could find a fit.

    Reviewed 5/11/2023
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    Hip to knee warm, cool indeed
    by SWF Rider
    Cycling Enthusiast
    SW Florida
    1 of 1 customers found this review helpful.

    The bib shorts performed as advertise. The material is supple and hip to knee hugged the leg. I would have preferred if the waist area was a little higher, but that would not deter from buying a second Nano Flex bib. Great for your cooler rides.

    Reviewed 3/14/2022
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    1st time Castelli purchase
    by Rick C
    2 of 4 customers found this review helpful.

    1st time trying Castelli, definitely not the last. Fit is perfect. Quality is top notch. I wanted to make an investment since I was spending so much time on the bike. I'm never going to sell my ass short again.

    Reviewed 12/21/2020
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    Warm and Huggy
    by SWF Rider
    Cycling Enthusiast
    SW Florida
    1 of 2 customers found this review helpful.

    This bib short perform as described. The XL fit was snug but not restrictive. a go to bib for cooler temperatures!

    Reviewed 1/14/2022
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