Like this site? Help us to make it better.

Castelli Nanoflex Leg Warmers



Warm, comfortable leg warmers with the added bonus of being water repellent.

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

What the scores mean

Good scores are more common than bad, because fortunately good products are more common than bad.

  • Exceptional
  • Excellent
  • Very Good
  • Good
  • Quite good
  • Average
  • Not so good
  • Poor
  • Bad
  • Appalling

Castelli's Nanoflex Leg Warmers are well designed and comfortable with the added bonus of being water repellent.

We've reviewed Nanoflex kneewarmers and armwarmers on in the past and we've been impressed.

The big selling point here is the water repellency of the Nanoflex. Castelli use their Thermoflex (a brush-backed Roubaix) fabric with the addition of "tiny silicone nanofilaments on the surface". This results in water beading up and rolling off.

Castelli don't claim that Nanoflex is completely waterproof. It'll keep road spray and showers out but harder rain does work through, especially through the bit at the front of your knee that you stretch repeatedly as you pedal. But the point is, these feel like any other leg warmers in terms of feel and breathability – like most, they're made from nylon and Lycra – so there's no down side to that extra water repellency.

How long does the Nanoflex keep doing its job? Well, I did a little test and found that the knee warmers I have from a couple of years ago that have been through the washing machine a zillion times weren't doing much in the way of keeping water out any more. Arm warmers from about a year ago that have been through the wash a couple of dozen times were still doing well.

I contacted Castelli's UK distributor, Saddleback, to find out if that was to be expected and they said: "Light ironing over the surface will rejuvenate the protection."

That's what I did and – hey presto! – it worked. I wouldn't say that the performance is right back to original levels, but it's not far off.

Nanoflex aside, these are good leg warmers in their own right, coming with just one flatlock stitched seam up the back, which I haven't found at all irritating. The elasticated gripper has silicone on the inside to hold it against your leg, and on the outside to keep it in place against your shorts. I've never had any trouble there. A YKK zip at the back makes getting them on and off easy, even over your shoes.

Castelli give a temperature range for every item of their clothing and we usually agree with them. In this case, they say 8-16°C. You could wear these when it's a little colder than that, but chances are that if it's that nippy there's no chance you'll want to remove your leg warmers mid-ride, so you might as well go for tights.


Warm, comfortable leg warmers with the added bonus of being water repellent.

If you're thinking of buying this product using a cashback deal why not use the Top Cashback page and get some top cashback while helping to support your favourite independent cycling website test report

Make and model: Castelli Nanoflex Leg Warmer

Size tested: Large, Black, 2 sent

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

Castelli say:

- Water -resistant Nanoflex fabric

- Same breathability, stretch, and warmth as our standard Thermoflex warmers

- Double-sided silicone grippers keep the warmers in place

- Ankle zips

- Great in every possible condition

Tell us some more about the technical aspects of the product?

Castelli say, "We always strive for total performance and total innovation, but sometimes we surprise ourselves. This NanoFlex fabric behaves just like our Thermoflex fabric in dry conditions, but then provides unbelievable water repellency when it starts raining. We don't claim that it's fully waterproof, but it's the most effective thing we've ever made for keeping you comfortable in all conditions. It's just barely short of a miracle."

Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:

The logos started to crack quite soon, but that doesn't affect performance.

Rate the product for comfort, if applicable:
Rate the product for value:

Did you enjoy using the product? Yes.

Would you consider buying the product? Yes.

Would you recommend the product to a friend? Yes.

Overall rating: 8/10

About the tester

Age: 43  Height: 190cm  Weight: 75kg

I usually ride:   My best bike is:

I've been riding for: Over 20 years  I ride: Most days  I would class myself as: Expert

I regularly do the following types of riding: commuting, club rides, sportives, general fitness riding,


Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.

Add new comment


jarredscycling | 10 years ago

although a tad pricey for leg warmers the benefits of a really great pair versus an okay pair can't be overstated

Colin Peyresourde replied to jarredscycling | 9 years ago
jarredscycling wrote:

although a tad pricey for leg warmers the benefits of a really great pair versus an okay pair can't be overstated

World peace is achieved with great leg're right!

russyparkin | 10 years ago

by the beard of zeus! it only bloody works!

russyparkin | 10 years ago

oh er! just ironed my arm warmers, now for some rain.

as an extra bit of advice take them off to iron them though, i now have barely any arm hair left now.

William Black | 10 years ago

Ironing also rejuvenates the DWR on Gore-Tex and most other fabrics.

CDK1962 | 10 years ago

Iron on the fleecy side or the outside please? - I have the same problem

Mat Brett replied to CDK1962 | 10 years ago
CDK1962 wrote:

Iron on the fleecy side or the outside please? - I have the same problem

On the outside. Don't go over the white logos.

Latest Comments