Sportful Stelvio jacket

The new Stelvio waterproof jacket from Italian company Sportful is one of the most waterproof and breathable rain jackets on the market right now, with an impressive performance as a result of being tested by professional cyclists in the most demanding races, but it's horribly expensive when compared with the game-changing Gore One Active jacket.

• Pros: Waterproof, breathable, comfortable, cuff details, bright yellow colour option, durable
• Cons: Expensive, not as breathable, light or packable as Gore One Active

Battling conditions, namely wind and rain, are the toughest tests a cyclist, professional or amateur, arguably faces, and clothing companies have been doing battle in recent years to provide the most advanced clothing that delivers the necessary protection while also being comfortable, lightweight and breathable.

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The new Stelvio ticks those boxes. It's made from a fabric called RainWick, a three-layer construction with a waterproof membrane and a DWR finish. Sportful developed the fabric itself, working with a Japanese textile company. It could have simply picked a fabric off the shelf like many brands do, but instead chose to develop its own at presumably great costs.

Naturally, the fabric is waterproof. Sportful gives it a 20,000mm rating, an industry test where a 1in diameter tube is placed over the fabric and filled with water until it starts leaking through; the higher the water (here, 20m), the more waterproof the fabric is. I've worn it during some astonishing rainfall, the sort that you really should seek shelter from, and the Stelvio has shrugged it off. The seams are all taped, as is the front zipper, and there are no weak points. Sometimes jackets can eventually let in the water around the shoulders, a high exposure area with a lot of necessary seams, but the Stelvio passed that challenge with flying colours.

Another key advantage of this fabric is the high level of breathability. Making a jacket waterproof is easy; the big challenge is producing a waterproof jacket that prevents the dreaded boil-in-the-bag syndrome. Quite simply, if the jacket isn't suitably breathable, you'll overheat inside it, and things can get very unpleasant very quickly. It's partly why Gabba-style jacket/jerseys have become very popular in recent years because they're more breathable than hardshell jackets.

The Stelvio is one of the most breathable waterproof jackets I've tested. To put some numbers on it, Sportful says the Stelvio's RainWick fabric has a 50,000g/m2/24hrs rating (achieved by a test of water vapour passing through a square meter of fabric). In reality, that meant I could ride at a brisk pace with the jacket zipped fully up, in the pouring rain, and the breathability prevented overheating and uncomfortable sweating. It really is remarkably good.

Now, testing breathability in the real world is a tricky business, principally because there are so many variables involved. Your pace and intensity level, rider weight and fitness, temperature and humidity levels, they all play a factor in the breathability performance. I usually run a bit cold (I like to wrap up when there's a snifter of a cold breeze) and the Stelvio impressed me in a wide range of conditions, from warm showers to cold downpours. Critically, for the UK at least, the breathability is sufficient that you don't have to remove it the minute it stops raining, or at the foot of a long hill.

The fit of the jacket is enhanced by the small amount of stretch built into the fabric, along with smartly shaped and placed panels. It's classic Sportful racy close fit fare, but provided you get the size right, the shape is excellent: good in the torso and generous in the shoulders and arms. I'm a size small in Sportful and the Stelvio fitted very well; the only time I had an issue was with loaded pockets, things got a bit snug then. I guess pro cyclists don't have to worry about pulling a jacket on overstuffed pockets, do they? On the up-side, the close fit means there's no buffeting at high speed, the jacket doesn't do the inflatey thing that many do, and it's quiet as well.

A smart feature is the double elasticated cuff design. To ensure the jacket is easy to get on and off over gloves, while also ensuring the cuffs provide a good seal around the wrists and prevent the forearms billowing, there's a double stitched cuff that provides a bigger opening but snugging it closer a couple of inches further up the arm.

There aren't many more details to talk about. There's a generous dropped tail that is low enough to cover your bum to protect from rear wheel spray. There are no pockets, they'd only add weight, bump up the price and introduce potential weaknesses in the jacket. There are a few reflective details but, as ever, a few more would be nice for a jacket that is going to be worn out on the public road at a time of year when light levels are low. A bright yellow colour is available and would be the one to choose for maximising visibility.

Take the jacket off and it rolls up fairly small and you can get it inside a jersey pocket. However, it's nowhere near as compact once rolled up as the Gore One Active jacket, and does require some careful folding and rolling to get it as small as possible. The Stelvio also isn't as light as the Gore One Active, but you only really notice the difference when you're carrying it your jersey pocket.

The Stelvio is a highly impressive waterproof jacket. It will protect you from the heaviest and most sustained rainfall; I've managed several hours in the constant rain and remained completely dry underneath. The breathability is similarly impressive, and a significant step forward from previous generation waterproof jackets. The cut, shape, fit and attention to detail all contribute to the jacket's high quality feeling.

However, any review of a waterproof jacket can't be complete without comparing it to the Gore One Active jacket, the current benchmark for waterproof jackets. Gore has been a market leader in the development of waterproof fabrics and its latest is a genuine breakthrough in breathability and lightness, thanks to its two-layer construction.

The Stelvio compares favourably with the Gore when the rain is hammering down, but the Gore noticeably has the edge in breathability; it simply copes with a wider range of temperatures better, and can even be worn when it's not raining, massively increasing its usefulness to cyclists at this time of year.

The Gore is also much lighter and folds up way smaller, taking up much less space in a jersey pocket. The Stelvio does boast better durability than the rather delicate-feeling Gore, and it comes in a bright yellow colour option as well as the grey one pictured here – the Gore only comes in a dull grey.

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Long-term durability has been really good, with no sign of the waterproof effectiveness fading over time, and it's really looked after me on some of the wettest bike rides I've ever enjoyed/suffered.

The Stelvio comes with a big price tag to match its big performance, though, and the list price is a lot higher than the Gore One Active. Shop around and you can find it discounted, at which point it becomes a more interesting purchasing prospect. There's a lot to like about the Stelvio: it's waterproof, breathable and very durable, and visible if you opt for the yellow option, factors that might make it a better option than the potentially more delicate and colour-limited Gore One Active.

Verdict

Impressively waterproof and breathable, with great fit and comfort, but big price tag