Skip to main content

Castelli Idro Pro 3 Shakedry jacket review

Does Castelli make the best Shakedry jacket on the market?

Castelli Idro Pro 3 shakedry rain jacket front view
(Image: © Josh Ross)

Our Verdict

Staying comfortable in sustained rain requires a hard-shell and riding hard requires real pockets. The Castelli pockets aren’t perfect but there’s nothing else like it on the market.

For

  • - Completely waterproof and breathable
  • - Large plastic zipper
  • - Pockets
  • - Long tail
  • - Excellent neckline

Against

  • - Shakedry technology means no stretch in the pockets

In the American Pacific Northwest, rain is a way of life. Average precipitation means more rainy days than dry, so if you want to ride then you are going to have to deal with rain and in this area of the world, Shakedry is almost a religion. 

Our list of the best waterproof cycling jackets has more than one Shakedry option on it. One of those is the Castelli Idro Pro 2 and when we looked at it more closely, we gave it a five-star review. However, Castelli recently updated that jacket with the Castelli Idro Pro 3 and now we've had a chance to see if it's as good as its predecessor. 

If Shakedry has your interest piqued, or if you are looking to update an old favourite, keep reading to see what we think of this new option. 

Castelli Idro Pro 3 shakedry rain jacket rear view

The new version should be considered an evolution of the older design (Image credit: Josh Ross)

Design and aesthetics 

The Castelli Idro Pro 2 jacket is a jacket that's been in the market for over three years. When it comes to cycling clothing, that's a lifetime, and it's no surprise to see an update hitting the market this year. The reason for the long timeline is that the core technology hasn't really changed. 

The Idro Pro 2, 3, and also the standard Idro (lacking the pro tag) are all built from a Gore brand technology called Shakedry. What makes Shakedry unique is that the membrane is the outer layer. With a standard Gore-Tex jacket, you have a face layer, a membrane layer, and a backing layer. Shakedry drops the face layer and moves the PTFE - also known as Teflon - membrane to the outside. 

Not only is the membrane waterproof and breathable, using millions of tiny holes that are large enough to let vapour out but not let liquid in, but it's non-stick. When water hits the surface, it will bead up and run off. Even if it was able to eventually get through, it doesn't absorb and it doesn't stay on the surface. Removing the face layer also keeps the material exceptionally thin, light and thus, packable. 

That technology is what makes all Shakedry jackets what they are. The biggest issue is that there's no stretch in Shakedry. Enter Gore-Tex fabric with Stretch Technology, which is a four-way stretch fabric that keeps all of the breathability and waterproofness of Shakedry but adds the necessary stretch. The only downside of the material is that it's heavy. It's the interplay of these two fabrics where brands go their own direction and differentiate. There's also some creative license when it comes to extra features. 

For Castelli, there are three big things that make it different from other Shakedry jackets on the market. At the back you have pockets, and real useable pockets at that, in the same two-pocket, glove-friendly configuration as other Castelli winter designs. There are drains at the bottom so you don't end up with puddles in them, and below those is an extra-long tail to handle road spray. At the top of the jacket, the neckline is tall, with a soft inner layer. 

The difference between the Idro Pro 2 and the Idro Pro 3

As mentioned, the Idro Pro 2 and 3 are very similar because the underlying technology isn't different. What Castelli has done with the Idro Pro 3 is refine and massage an already solid design. When you compare the two, there's an optimisation and a simplification of the pattern. 

The Idro Pro 2 sees the use of numerous small pieces of Gore-Tex fabric with Stretch Technology. In the Idro Pro 3, the stretch panels have been moved, and now, both sides are entirely built from Gore-Tex fabric with Stretch Technology and it continues through the armpit and down the underside of the arm to the wrist. 

Other small differences are also simplifications. The top edge of the pockets lose the elastic edging and the bottom gusset no longer uses a different fabric. The whole pocket is now Shakedry. Below the pockets, the silicone gripper has disappeared and the bottom edging of the tail is reflective with more stretch than the previous design. 

Castelli Idro Pro 3 detail image of the GORE-TEX Fabric with Stretch Technology

Gore-Tex Fabric with Stretch Technology has similar qualities as Shakedry but it adds weight and stretch. (Image credit: Josh Ross)

Performance

I use the Castelli Idro Pro 3 anytime I plan to head out in rain that I expect to last all day. It's warmer than you'd think because it's just as windproof as it is waterproof. The lack of insulation does limit it to some extent but a low bulk insulative layer like the Assos Equipe RS Winter Long Sleeve Mid Layer, or any of the best winter cycling jackets would allow it to push into seriously low temperatures. 

The pockets are the real trick here. If you are riding hard - or racing - you need access to food without thinking about it. When you are racing in bad weather that doesn't change, except now you'll need to find a jacket that gives you that option. The Castelli Idro Pro 3 has pockets with room for food and it manages that with an aerodynamic cut. It's a perfect jacket for hard riding and racing in the rain.

Castelli Idro Pro 3 detail image of the rear pockets

The dual pockets that are open at the tops are one of the best features of the Castelli Idro Pro 3 (Image credit: Josh Ross)

The downsides to the jacket have more to do with Shakedry than anything else. The lack of stretch is a big one. Castelli sizing works extremely well for me but even though the jacket fits perfectly the lack of stretch in the pockets is a challenge. Castelli has mitigated the issue with a gusset at the bottom of the pockets but there's still a limit to how much you can stuff them full.

Some of my favourite aspects have to do with the details. I love the neckline that Castelli uses, as it's soft on the inside and nice and high to keep the cold out. The zipper is also a real high point, it's similar to the older version but with an added pull tab. It retains the big, plastic, teeth that make it easy to zip and keeps it immune to degrading from sweat. Most of the time with an expensive jacket, it's the zipper that will kill it, but there's no worry about that here.

Castelli Idro Pro 3 detail image of the pocket drain holes

Shakedry lacks stretch but the gussets in the bottom of the pockets help make more space. (Image credit: Josh Ross)

Verdict

If you want to ride all day in the rain then you need a hardshell jacket. Out of the available hardshell technologies, Shakedry is the lightest weight option. Gore and Castelli each have Shakedry options with pockets but only the Castelli Idro Pro 3, and its predecessor, has open pockets like a jersey.

The pockets, coupled with the smaller-than-average Castelli fit, makes the Idro Pro 3 perfect for training hard or racing in the rain. It's particularly great for gravel racing, or just riding, since mud won't hurt it. 

If you have an Idro Pro 2 there's no need to think about upgrading until you need to replace it. Otherwise, if you are looking to ride all day in the rain The Castelli Idro Pro 3 is an excellent choice.

Tech Specifications: Castelli Idro Pro 3 

  • Price: £360.00 / $399.99 / €359.95 / AU$599 
  • Colour: Black
  • Material: Gore-Tex Shakedry, Gore-Tex Fabric with Stretch Technology
  • Weight: 179g (size small)
  • Size availability: S, M, L, XL, XXL, 3XL
  • Temperature Rating: 6°-20°C / 43°-68°F