Kalf Flux Transition windproof jersey – review

Top-quality windproof jersey and another impressive piece from Kalf

Keith Bonrager famously once said “strong, light, cheap; pick two” about bike components and it’s a conundrum that continues to trouble riders today. As for clothing, the same may apply but for ‘performance, style and value’. However, the Kalf Flux Transition jersey ticks all three boxes.

Kalf launched earlier this year and is a new clothing brand available exclusively at Evans Cycles. We’ve already been really impressed with the Flux Chevron short-sleeve jersey and Flux Chevron bib shorts – and they were no fluke. The theme continues with the Transition.

The clue is in the name – the Transition is a short-sleeve, windproof jersey best-suited to the transition (or shoulder) seasons of spring and autumn. The front of the jersey (that is to say the chest, shoulders and front of the sleeves) features a lightweight, windproof membrane, while the rear and back of the sleeves are made from a breathable polyester yarn. The idea is to keep the wind off your chest (which also has a DWR water resistant treatment), while allowing heat to escape from the rear.

The Flux Transition is an excellent windproof jersey from new clothing brand Kalf
  • Specification

  • Price: £74.99
  • Sizes: XS-XXL
  • Size tested: M
  • Website: Evans Cycles

We’ve seen windproof jerseys crop up from almost every clothing brand since the Castelli Gabba first made waves, but the Transition is lighter than most – it’s not a softshell. It’s certainly lighter than the Gabba, but also more svelte than the Castelli Perfetto launched last year (as a lightweight version of the Gabba).

Still, the windproof front does an excellent job at keeping the breeze at bay, while the water resistant treatment is effective at providing some protection against road spray and light rain or short showers. Needless to say, it’s no substitute for a waterproof jacket (the polyester fabric doesn’t have any kind of water resistance, for starters), but it’s capable of providing some protection in those uncertain conditions when there could be a little rain on the horizon. It also means you don’t have to reach for a rain jacket quite so quickly.

Because the windproof membrane is pretty light, it does a good job at maintaining breathability – better than many, that’s for sure. The polyester fabric away from the windproof panel helps, particularly under the arms. It should be said, however, that any windproof fabric will begin to struggle if you’re working particularly hard or the temperature stretches outside of the garment’s limits. However, the Flux has a full-length zip, so it’s easy to vent the jersey if setting a pace up a climb.

As for the temperature range, I’d be happy reaching for the Flux Transition jersey on a ride with the temperature anywhere between about eight degrees if riding at a brisk pace and 16 degrees. That will depend on how warm you run, of course – and you can get away with the jersey in slightly cooler morning temperatures if it’s expected to warm up.

Attention to detail is very good, with this gripper helping to keep the jersey locked in place

Why wouldn’t you just wear a gilet over a summer short-sleeve jersey? That’s definitely an option and something cyclists have been doing for years, us included – and we will continue to do so. But a jersey like the Transition provides a little more focussed protection in one piece, without compromising anything else, such as fit.

On that, the fit is excellent (our model is wearing a size medium). It’s a race-cut piece, so the fabric is figure-hugging and follows the contours of the body without any overly tight or baggy areas. The neck is made from a stretchy fabric so fits comfortably, and the same goes for the material used under the arms, on the back of the sleeves and on the rear of the jersey. Still, it’s a close fit, so if you want something a bit more relaxed, consider going up a size.

Kalf Flux Transition windproof jersey
Kalf Flux Transition windproof jersey
Kalf Flux Transition windproof jersey

Attention to detail is excellent, too. There are six pockets in total, with the usual arrangement of three rear pockets, as well as a well-sized, central zipped pocket. On top of that you’ll find two more hip pockets, one on either side of the jersey. These are ideal for carrying small things like keys or, more handily, energy gels or bars, because they’re really easy to access. This isn’t the first jersey we’ve seen side pockets on, but it’s a smart move nonetheless.

Otherwise, there’s a generous amount of reflectivity on the rear, with a large Kalf logo and detailing around the zipped pocket. We’d like some on the front as well, though. Meanwhile, the rear of the jersey has a large and sticky gripper that holds the jersey in place well. The sleeves are slim and so don’t need any kind of gripper. As for style, that’s subjective, but we think the ‘merlot’ and black combination is very smart, though it’d be nice to see a couple more options.

Kalf is available through Evans Cycles

And the price? £74.99. Compared to more established brands on the market, and given the performance and fit of the piece, that’s a steal.


The Kalf Flux Transition jersey is a rare piece of kit indeed. As a windproof jersey, it’s naturally a more niche product than a typical short-sleeve jersey, but it’s a piece that will find a lot of fans among UK riders in spring and autumn. Throw in the smart styling, excellent fit and attention to detail, and this is a top piece of kit from the new brand. Very impressive.


  • Lightweight windproof protection ideal for spring and autumn
  • Maintains fairly good breathability
  • Excellent race-cut fit
  • Six pockets provide plenty of storage
  • Stylish design and high attention to detail


  • More reflectivity on the front would be welcome
  • Riders wanting a more relaxed fit may need to size up


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