Kalf Flux Transition Wind Proof Jersey

Wow, Kalf has really impressed us with its new range of products this summer. We loved its bibs, Chevron summer jersey and mitts, scoring all of them highly, and I have to tell you that this, the Flux Transition Wind Proof Jersey, might be the pick of the range. It's available nationwide via Evans, and it pretty much nails the newest niche on the block: the lighter-weight windproof jersey.

The Transition is made from two very different fabrics. At the front is a three-layer fabric laminated with a high performance windproof membrane, and the rest of the jersey is made from a lightweight fabric woven from ASKIN yarn, claimed to be soft to the touch, cooling, breathable, fast drying and with UV protection.

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The windproofing covers the front of the torso and also the front and outside of the sleeves, and is very effective. Kalf told us that it's also treated with a durable water resistant (DWR) coating and the membrane is rated to give water resistance to 10,000mm and a breathability rating of 10,000g/m2/24h.

I've used it in a range of conditions and it excels on changeable days when the temperature is the teens. Unless I'm pootling, I get too hot in a Gabba once it's much more than 10 degrees, and so this fills a useful gap in the wardrobe for me. It's not a jersey for hot summer days, at least not for me, as the windproofing would mean I get too warm; I'd typically eschew water protection and just get wet if it rains on hot days.

The use of a very stretchy and breathable fabric for the sides and back of the jersey offers a number of benefits. Firstly, it helps with the fit. As with the Chevron jersey, the fit here is pretty much spot on if you like your jersey to sit close to you. It's certainly not tight like some jerseys where you have to yank the two halves of the zip together to get it on, and it's certainly not flappy or baggy; it's like the third bowl of porridge – just right.

My 39in chest makes me a medium per the sizing guide, and the supplied medium fits beautifully. That's not me in the pictures, but our model Ash is the same height and weight as me. The close fit is facilitated because of the give in the back and sides of the fabric, as the softshell fabric at the front is not stretchy.

The second benefit of the combination of fabrics is to help prevent overheating. Humidity in the armpits can quickly escape and heat is easily shed from your back too. If you're going hard on a warmer day, you may find you want to open the zip a bit, as with any windproof, but in general I found that it works really well in the range of around 10-18 degrees. Skin comfort across the front of the chest is improved on warmer days through the use of a mesh baselayer underneath, although I was fine without this throughout most of the testing.

Kalf hasn't overlooked the details, and there are some unusual touches here, most notably with the pockets. At the back you have the regulation three pockets with a zipped pocket on top of the central one that's large enough to keep a large modern smartphone safe (but not dry). So far, so standard. But then – what's this? Carry on round to the sides and Kalf has stuck a further pocket either side of the normal three, sitting around your hips.

Sounds odd, and the first few times I wore the jersey I simply forgot they were there. They're made of the same stretchy material as the back panel and so if you don't put anything in them, they sit flush and don't catch the wind at all. They're great for putting things like gels in, making it just a bit less of a contortion to access the contents while riding. I put my keys in there to see if they fell out (we take the risks so that you don't have to, reader) but the material clung tightly to the bunch and there was no way they were going to get ejected.

What's that you're saying? How does this compare to the plethora of other windproof, water resistant jerseys now available? Well I'm glad you asked. It is notably lighter-weight and less insulating than the Castelli Gabba, Parentini Mossa and the Orkaan from Stolen Goat, and has much more in common with the Perfetto that Castelli added to its range last year. That has a similar arrangement of lightweight windproof fabric on the front and a more breathable and elastic fabric on the back, with the main difference being the Nano Light Pro fabric used on the back of the Castelli top has a water-resistant coating. The Perfetto is significantly more expensive at £125 RRP, although is widely available online for a lot less than that.

> Design classic: Castelli's Gabba

The Transition is only available in the dark colours seen here, dubbed Merlot by Kalf, and to my eyes it looks pretty smart. There is subtle branding on the front – just a couple of Ks – and then a rather pleasingly psychedelic reflective decal on the back. Rapha-esque styling meets Castelli performance at sub-dhb prices, anyone?

As you'll have gathered, I was really impressed with the Kalf Flux Transition jersey. Sure, you could argue that a gilet over a regular summer jersey could give you similar protection from wind and rain, although I really liked how that protection extended to the front of the upper arms here. My first thought about the pockets was "is it just a gimmick?" but having used it, I found myself wishing that some of my other jerseys had the same feature for those really long rides where you need to carry lots of stuff.

Throw in careful detailing and the surprisingly keen pricing – £20 less than the dhb Aeron Rain Defence jersey – and I reckon Kalf and Evans are onto a winner here.

Verdict

Smashing weatherproof jersey for unpredictable warmer days at a great price – highly recommended