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Castelli Nanoflex Leg Warmers

$55.96 $69.95 20% off

Item # CST2614

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  • Black, S ($55.96)
  • Black, M ($55.96)
  • Black, L ($55.96)
  • Black, XL ($55.96)
  • Red, S ($55.96)
  • Red, M ($55.96)
  • Red, L ($55.96)
  • Red, XL ($55.96)
  • White, S ($55.96)
  • White, M ($55.96)
  • White, L ($55.96)
  • White, XL ($55.96)
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Item # CST2614

Warm and dry never looked so good.

If there's one failing to most legwarmers, it's that they absorb water like a proverbial sponge. On rainy days, they end up waterlogged and providing compromised warmth. However, the Castelli Nanoflex Leg Warmers are perfect for riding in conditions that are both cold and wet. Then again, outside of Mojave heat levels, we can't think of any condition that won't benefit from Nanoflex.

Nanoflex is a proprietary Castelli fabric. The mill begins with Castelli's super-warm and ultra-stretchy Thermoflex fabric (used in many of its winter pieces) receiving an exterior coating of ultra-tiny nanofilaments of silicone fiber. These fibers create a near waterproof barrier to moisture, and raindrops run off the fabric without soaking through. Despite its water-resistant finish, Nanoflex fabric remains highly breathable, keeping you comfortable in almost any condition.

Silicone leg grippers keep the Nanoflex legwarmers in place on the hardest of rides, and ankle zips make them easy to get past the largest feet. And lastly, reflective logos are printed at the knee and below the calf in order to increase your visibility to motorists in low-light conditions.

The Castelli Nanoflex Leg Warmers are available in four sizes from Small to X-Large and in the colors Black, Red, and White.

Tech Specs

[warmers] Nanoflex
Cuff Closure:
silicone gripper
Recommended Use:
cool weather road cycling
Manufacturer Warranty:
30 days

Size chart


Arm and Knee Warmers
Rider Weight 99.2 - 132.3lbs
(45 - 60kg)
132.3 - 154.3lbs
(60 - 70kg)
154.3 - 176.4lbs
(70 - 80kg)
Short Size XS - M S - M L - XL 2XL - 3XL
Short Size:
Take your typically cycling short or bib sizing for comparison.

Reviews & Community

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Castelli Nanoflex Leg Warmers

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Here's what others have to say...

1 5

Tore up after one wear

  • Familiarity: I've used it once or twice and have initial impressions

I wore it only once and after one wear. Even worse is apparently since I bought it a bit early (in September) I am ineligible for an exchange or refund.

5 5

One leg warmer to rule them all

  • Familiarity: I've put it through the wringer

I have had nothing but great experiences with this leg warmer.
First the fit, is great. I am 6'1" about 160 pounds and I chose a medium. I had some slight bunching up on the back of the knee but no discomfort like others have had. The bottom zipper also did not create any irritation by the ankle which I have seen in some leg warmers. Warm enough to keep me warm in ~3 degree celsius temps and cool enough in 20 degree celsius. Overall excellent leg warmer and highly recommended, if you have an issue it is probably due to improper sizing.

1 5

Like sandpaper

  • Familiarity: I've used it several times

The fleeced interior on these is like sandpaper. Too rough to wear on even a few warm-up laps at a cyclocross race.

1 5

not great for actual movement

  • Familiarity: I've used it several times

I was disappointed in these, I usually have enjoyed Castelli's clothing a lot. They seemed like they fit great when I firt put them on but when pedaling (bending your knee's) it bunched on the back and rubbed. I see that a lot of other reviewers had similar circumstances. I would suggest another brand of leg warmers, I have some craft that work better.

Responded on

I just wanted to add that my problem is with the seam, and the rubbing it generates on the back of the knee. I consistently get enough rubbing from that seam on the back of my knee that it rubs the area raw and eventually scabs. I really like these warmers, however I wish Castelli would do something about minimizing or reworking that seam.

5 5

Cyclocross Must Have

  • Familiarity: I've put it through the wringer
  • Fit: Runs small

These things are great for cyclocross.
They repel water really well and are nice and warm. Tight fitting as most Castelli gear is, but also very stylish!

3 5

Works well but watch sizing.

  • Familiarity: I've put it through the wringer
  • Fit: Runs small

I have used these in an extended rain ride. The water beads off like it is supposed to. The nanoflex stuff does not stretch like normal warmers do. I ordered a size L, but really need an XL. Like another reviewer here, the seam rubbed the back of my knee raw. In this case the seam was not in the middle of my leg, while the warmer on the other leg was and did not experience rubbing. The seam needs to be exactly in the middle to avoid the rubbing. At least with my legs.

1 5

Feels Like Cardboard

  • Familiarity: I've used it once or twice and have initial impressions
  • Fit: Runs small

I'm not sure what Castelli had in mind with these, but they felt like I was wearing cardboard. At the end of a 50 mile ride, the skin at the back of my knees was rubbed raw.

How does one decide between the Nanoflex...

How does one decide between the Nanoflex and Thermoflex leg warmers, other than price? In other words, why would you choose one style versus the other? Thanks.

Best Answer Responded on

Confucius say - go with the Thermoflex :) Almost the same :)

Responded on

The nanoflex is very water resistant, so I'd pick the nanoflex if the weather is iffy. For cold and dry, pick the thermoflex.

4 5

The only way to go

  • Familiarity: I've put it through the wringer

The nonflex are the only way to go. Great item, and allows you to reduce the amount of winter wear, without feeling the effects of the cold

4 5

Runs small

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

I ordered a small, like all other legwarmers ever. I am a female and usually wear small shorts and leggings. I couldn't get these over my calves as a small, so I am returning them. I can't speak to the quality, but they seem nice like all other Castelli stuff.

3 5


  • Familiarity: I've used it several times

Just put these back on after a hot summer and noticed that the material around the knees was flaking off. Not sure this is designed to happen after one season.

Unanswered Question

What is the durability of the water...

What is the durability of the water resistance of the nanoflex over numerous washings of the garment?

Unanswered Question

What is the length of the small leg warmers?...

What is the length of the small leg warmers? Do they come in XS? Thanks!