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Castelli Inferno bibshort



Keep you cool when the going gets hot. Comfy chamois and top fit

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.

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Castelli's Inferno bib shorts, as you can probably guess from the name, have been designed to excel when riding in the hot weather. They've used seven different fabrics to make a short that keeps you cool and prevents overheating, combined with one of the most comfortable inserts, the Progetto X2 Air, I've ever tested.

The Infernos were created at the request of the professional cycling team they sponsor, Garmin-Sharp, for a short designed to cope with the hottest days. They achieved this by using very thin and lightweight fabrics with mesh panels all carefully placed to offer very high breathability.

Pull them on and they do feel lighter and airier than regular shorts. Go for a ride in them and you can feel the air passing through the fabric. I tested them in Italy recently where the temperature nudged into the low 30s, and they lived up to their billing: I felt cooler and more comfortable.

Cleverly, for a short designed to be used when it's hot, they've incorporated a titanium dioxide into the fabric to act as a sunscreen to reflect harmful UV rays. And they realise that shorts used in hot weather are going to be some of the longest days in the saddle, so they've added an abrasion-resistant nylon fabric on the side of the legs to they don't wear out prematurely.

Fit, as is always the case with Castelli, is excellent. It's Italian so it's on the snug side, but there's enough stretch in the fabric that they don't feel at all tight or restrictive when pedalling. They come in sizes from small to XXXL and I would heartily recommend trying before you buy. The bib straps are stretchy and slip comfortably over the shoulders, and the back panel is one big piece of mesh material to aid the base layer's ability to wick sweat away.

There's also a small race radio pocket in the back as well, but that's a pretty pointless feature for us mere mortals. It is a good place to store an MP3 player though. I largely didn't use it at all though.

Castelli are moving away from the traditional silicone leg grippers to large elasticated hems, which they call GIRO3. These are extremely comfortable with no irritating silicone and the legs stay firmly put, with no evidence of them riding up during riding.

Inside is the real business end of the shorts, the Progetto X2 Air seat pad. We've said in previous reviews how comfortable this pad is, it's really one of the best on the market at the moment. It's a two-layer design with a stretchy cover and separate padding beneath, the two are free to move over one another, reducing the chance of anything rubbing, and causing irritation.

Which just leaves the price. Yes, they're expensive. Here's the thing though, comfort when cycling is the most important consideration and investing in the most comfortable shorts you can afford should be right at the top of your list. The comfort these offer is right up there with the very best. I've done loads of riding in them, and you barely notice they're there. You don't even feel the chamois. But it's there, keeping you comfortable mile after mile. There are a lot of shorts that cost a lot less and I'm not going to say these are two or three times better than those. If you are spending this sort of money though, then rest assured you won't be disappointed.

Available in six sizes and black or black/white.


Keep you cool when the going gets hot. Comfy chamois and top fit. test report

Make and model: Castelli Inferno bibshort

Size tested: n/a

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?

This Castelli Inferno Bibshort was created based on Team Garmin-Sharp request for a short for the blazing heat of Italy in May and France in July. We examined the specific function of each part of the short and used 7 different fabrics to make a short that is as cool as possible yet up to the task of performing for the most demanding riders on 7-hour mountain stages. The short fabrics are all white-based fabrics with sublimation printing over the top. We've incorporated titanium dioxide, the active ingredient in sunscreen, directly into the fabrics so that they reflect the sun's rays. Each part of the short features fabric that we feel is as open as possible while still providing some sun protection where necessary and avoiding transparency on the front and back. But this short is not just about staying cool. We've kept an abrasion-resistant ballistic nylon fabric on the inside of the leg but knitted it with wicking polyester on the inside to keep you dry. The leg ending is our renowned and often copied (though never equaled) GIRO3 elastic, and our Progetto X2 Air seat pad is used with its ventilated skin-care layer to keep you cool. The Castelli Inferno Bibshort keeping you cool in the heat of competition.

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

Progetto X2air seat pad for comfort and improved air flow on long days in the saddle.

7 different fabrics to maximise cooling

Giro3 single-layer engineered gripper.

2 rear reflective inserts.

Castelli screen print on both legs

Rate the product for quality of construction:

Excellent construction.

Rate the product for performance:

Fit and comfort is up there with the very best, these are excellent performers.

Rate the product for durability:

I've been testing them loads and racking up the miles and they're still looking as good as new.

Rate the product for comfort, if applicable:

The chamois is one of the most comfortable I've ever tested, it's like it's not even there, but it's fantastic even on all-day rides.

Rate the product for value:

You can certainly pay a lot more for bib shorts.

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

For riding in warm weather, either in the UK this summer or for any trips abroad, these are a good choice.

Tell us what you particularly liked about the product

Fit and chamois.

Tell us what you particularly disliked about the product

They're on the snug side, and will force you to think twice about those biscuits.

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: 31  Height: 180  Weight: 67

I usually ride:   My best bike is:

I've been riding for: 10-20 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, touring, mtb,


David worked on the tech team from 2012-2020. Previously he was editor of and before that staff writer at RCUK. He's a seasoned cyclist of all disciplines, from road to mountain biking, touring to cyclo-cross, he only wishes he had time to ride them all. He's mildly competitive, though he'll never admit it, and is a frequent road racer but is too lazy to do really well. He currently resides in the Cotswolds, and you can now find him over on his own YouTube channel David Arthur - Just Ride Bikes

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GerardR | 11 years ago

Castelli shorts are lovely, but be wary of the sizes. At 6'-1/2" and 13-1/2 stone, I am long-legged and had to return the XL size I usually take for an XXL. I'm not fat, barely well-rounded (ok, porky for a cyclist), but I suspect you need to take a size above your usual.

smitty | 11 years ago

It's interesting to note that the Garmin guys also use these on cool rainy days saying that they love how they don't hold water.

Just one note on the review: "Castelli are moving away from the traditional silicone leg grippers to large elasticated hems, which they call GIRO3." Uhhh...Castelli actually started this trend. Giro3 is already the 3rd generation.

Mat Brett | 11 years ago

Yes, that's a separate base layer, if that's the source of the confusion.

swldxer | 11 years ago

I think the model is wearing a separate vest - on Wiggle the shorts don't have a meshed front.

jezzzer | 11 years ago

How would pee stops work then?

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