Castelli Idro Pro 3 Jacket review – an utterly uncompromising 'hyper-jacket'

A jacket that uses the best materials available to great effect but it is very expensive

Castelli Idro Pro 3 Jacket
(Image credit: M. Grele)
Cycling Weekly Verdict

At $449.99 / £410 RRP this is a serious investment and a serious show of intent. You are getting the best materials available currently and that doesn't come cheap. This is a very focused design – it does one thing and utterly excels

Reasons to buy
  • +

    ShakeDry fabric is the most advanced currently available

  • +

    A very purposeful cut

  • +

    A supremely capable garment

Reasons to avoid
  • -

    ShakeDry fabric is expensive

  • -

    Slim arms make it hard to put on on the move

  • -

    Only available in Black

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The Idro Pro 3 jacket is part of Castelli's Rosso Corsa line, which is the Italian brand's highest tier of design and function. It uses Gore-Tex Shakedry fabric for the main body and arms, allied with a Stretch Gore-Tex fabric for the body sides and under arm areas to create a close fitting yet unrestricted garment. There is a YKK Vision waterproof zipper to stop water ingress too.

Its essentially a greatest hits of all the best waterproof cycling jackets rolled into one.

Image shows a rider wearing the Castelli Idro Pro 3 Jacket.

Showing the stretch side and arm panels

(Image credit: M. Grele)

Castelli Idro Pro 3 Jacket: construction

Gore-Tex ShakeDry has been available for a few years now and is still top of the pile with regard to water repellency allied with high breathability. It is a 2-layer ultralight waterproof breathable fabric and it is also very expensive! 

As it has no give, the Stretch inserts allow the jacket to still sit close to the body. A stretch panel measuring 12cm can easily expand to 17cm (without over stretching it) for example. Rather impressive.

The seams are fully taped, as you'd expect, and overall this feels like a really well made jacket. There are reflective trim sections all around the drop tail and cuffs, and whilst not massive they give some useful signals to following traffic at night.

There are two pockets (with drain holes!) on the rear of the jacket, and whilst not massive, they were useful to put a neck buff and skull cap in so that I didn't have to unzip to access the jersey pockets.

Castelli Idro Pro 3 Jacket: the ride

The cut is slim with a high front waist and a long drop tail. The sleeves are slim with contoured elbow sections and are nicely long. The cuffs are close fitting but with enough room to easily get a long cuffed glove underneath for extra weather protection and to create a good seal. 

When riding I felt the tightness in the jacket across my lower ribs as it stretched with my breathing. It wasn't a problem, though, just a bit different to what I'm used to. The jacket felt snug and you have a sense of purposefulness wearing it.

This isn't a rain jacket to top off a mutli-layered system on a bitterly cold day. You're likely to get a base layer, bib tights and a mid jacket/top underneath – but not much more. You could go up a size, but then you would lose the point of the cut being what it is. 

I found it warm enough with light layers underneath even on cool to chilly mornings. This is due to the highly windproof nature of the fabric along with the close cut keeping warm air close to the body, trapped in your under layers.

The zip is a chunky YKK Vision type which is also waterproof. It can be adjusted single handed easily and there is plenty of room for a high necked jacket underneath without the neck becoming too tight. The neck was a slightly looser fit than the Rapha Core II and dhb Aeron Lab jackets, yet I found no problem in the rain with it sealing nicely around my neck. There is a brushed lining to the collar which I liked, too.

The rain beads well on the surface and can easily be flicked off. Castelli claims that ShakeDry will shed rain better than any other fabric, and that feels right to me with my time with the jacket. 

I did find a small amount of condensation inside the jacket but I was quite hot after a fast ride and it was a high humidity day with moderate and constant drizzle too. There was no leak through or fabric drenching. Once the jacket was removed, shaken and hung up, it dried very quickly.

Castelli says that the jacket weighs 209 grams (no size stated), however I weighed the medium one as 181 grams. Whilst it does roll up small enough to fit in a jersey pocket it is a tight fit. Compared to the Rapha Core II – weighing 127 grams and which you barely feel rolled in a pocket – the Castelli is a slightly bulkier jacket. It fits into some jersey/jacket pockets better than others.

It is also only available in Black which, whilst cool, made me feel less visible to other road users, especially on night rides, as well as on rainy rides with lots of road spray. In this respect I preferred the Rapha Core II in Bright Orange. 

Castelli Idro Pro 3 Jacket: value and conclusion

At $449.99 / £410 RRP this is a serious investment and a serious show of intent. You are getting the best materials available currently and that doesn't come cheap. 

The Castelli Idro Pro 3 Jacket is a really focused design, to do one thing and excel at that purpose. It is a jacket that you would start a rainy ride wearing and expect to wear it for most or all of the day, and stay dry and comfortable during that time. Whilst it does roll up and is pocketable you'll need a jersey with larger pockets to accommodate it best. This makes it less of a 'just in case' jacket to my mind.

In comparison, the Assos Equipe RS Rain Jacket Targa looks a bit of a steal at $400 / £290 RRP – although I would say each is similarly uncompromising, just targeting different needs: the Assos RS Rain Jacket Targa is a little heavier and harder wearing.