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Castelli Fluido Bib Tights



Highly water-resistant bibs with windproof panels for warmth and an excellent seatpad; expensive, but they justify the price tag

Yes, Castelli's Fluido bib tights are expensive but they're also incredibly good at keeping out the wind and also protecting you from rain and road spray. You'll be amazed at the performance, these are the best bit of clothing I've tested in ages.

We've told you about Castelli's Nano Flex products before in earlier reviews but it's a story that's worth revisiting. Nano Flex is a fleecy Roubaix fabric that Castelli give a special magic coating. Well, maybe not magic but it's very clever technology that involves tiny silicone particles.

The result is a fabric that's soft, warm and breathable and also highly water resistant. It isn't completely waterproof. Rain can get through, particularly into the sections that flex most around your knees, but spray from the road and light showers just bead up and roll off. You have to see it to believe how effectively it works.


Most of the lower sections of these bibs are made from Nano Flex, but the front of the thighs and torso and the panel at the base of your back/top of your butt are made from new SG.06 fabric. This isn't as breathable or as stretchy as the Nano Flex but it is even more water resistant. It is fleece-backed and windproof too so it adds a lot of warmth.

If you get caught out in a proper downpour while wearing these, you'll get wet. But if the roads are wet and water gets sprayed up from your wheels, you'll stay dry. And you'll stay dry during intermittent showers too. Castelli promise water resistance rather than waterproofing and that's what they deliver.

The pulls on the YKK ankle zippers lock in place so they'll never come open as you pedal and reflective trim along the sides of them is really noticeable in car headlights. The lightweight ankle grippers are stretchy enough to wear either inside your overshoes or over the top. Why would you want to wear them over the top? Because the water that beads up on the legs has to run somewhere; you don't want that somewhere to be straight into your shoes.

The other excellent feature of these bib tights is the Progetto X2 seatpad. It's variable thickness with a maximum depth of 12mm, but its best feature is that it's constructed in two parts. You get one soft and stretchy layer next to your skin with the bit that does most of the work sitting underneath that. They're not fixed together so they can slide over one another slightly, and that minimizes rubbing as you move in the saddle.

That might sound like a lot of hocus-pocus too, but it works. This is an amazingly comfortable pad, doing the business throughout long rides. The single row of zigzag stitching around the side of the pad doesn't look terribly reliable but it's the same on several Castelli shorts and tights that I've used in the past and it does the job. You can buy the same tights without the pad for £145.

Castelli reckon these are suitable for zero to 10°C rides. It'll all depend on the individual and the intensity of the ride but that seems like a reasonable temperature range to me. If you get wet during winter, even if it's just a bit of spray from the road, you're likely to get cold soon afterwards. The main benefit of these tights is that they'll keep you dry –and if you're dry you're halfway to staying warm and enjoying yourself more.


Highly water-resistant bibs with windproof panels for warmth and an excellent seatpad; expensive, but they justify the price tag

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Make and model: Castelli Fluido Bib Tights

Size tested: Large

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, "Our top performing tight for cold or wet conditions. Our 4-way stretch SG0.6 Wind keeps the wind and water off the front bits, while Nanoflex water resistant fabric sheds the water from the rest. And it's made to ride the distance with our highly acclaimed Progetto X2 seatpad."

These features might sound gimmicky but they're really not; they genuinely work incredibly well.

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

Nano Flex works. You look at it and think there's no way it can stop water. It's soft, fleecy, warm... But water runs off it.

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

A score of 10 means excellent. The performance here is excellent.

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

Tricky. There's no denying that £170 is a lot for a pair of bib tights that'll wear out just like any others. But these aren't just some normal tights with a pretty logo. You're paying for technology that makes a real difference to your comfort and enjoyment. To me, that's worth paying for.

Tell us how the product performed overall when used for its designed purpose


Tell us what you particularly liked about the product

The water repellency.

Tell us what you particularly disliked about the product

There's no ignoring the fact that £170 is a lot of cash.

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: 9/10

About the tester

Age: 41  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: time trialling, 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 pushing 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.

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