The Ultralight Wind Jacket from B'Twin (Decathlon's in-house cycling brand) is a low-priced lightweight jacket designed to give you some protection when the weather catches you out. It stuffs into its own tiny pocket, about the size of a fist, and weighs very little, so it's no chore to keep it in your bag or pannier for when it's needed. As you might expect, it's aimed more at the casual cyclist than those wanting highly technical cycling wear, but it does a decent job especially at this price.
The jacket is made from what Decathlon describe as a windproof Biosphere fabric, which is 100% polyester, and is available in a translucent white or a bright fluorescent yellow colour. The fabric is very light - my scales gave a weight of only 87g for the jacket - but seems reasonably hard-wearing and rip-resistant. There are basic elasticated cuffs which do a decent job of keeping drafts at bay, but make it hard to take the jacket off without reversing the sleeves. A small external pocket with a toggled draw-string is just about big enough for a medium-sized phone, but its main function is to pack the jacket. It's a quick job to stuff it into the pocket and makes it easy to sling in a jersey pocket when the weather improves.
The reverse process is pretty painless too. I found I could fish out the pack, pull the jacket out and put it on without coming to a stop if needed. Once it's on, it does a good job of blocking the wind, making more of a difference to your temperature than you might imagine given how thin it is. Decathlon claims that it has some water repellence too, and I found that in a quick shower it would keep most of the rain out, but that's about the limit on that front. When worn over bare arms, the fabric would saturate and cling to your skin, which isn't that nice; having a long-sleeve jersey underneath helps here, as ever.
Stu reviewed the sleeveless version a few months ago, which is priced identically, and was really impressed, praising the packability and decent fit. I found the fit of this jacket to be less impressive. It's a pretty basic shape and when riding any bike with drop bars, the Large size I was testing was too tight across the shoulders, tending to pull the cuffs up my arms. With no sleeves, this obviously wasn't an issue with the gilet.
While the fit is relatively slim, the lightweight and inelastic fabric does mean that it's pretty flappy when going at any speed, acting like an air-brake at higher speeds. Rolling down some of my regular commuting hills I would top out at a few mph lower than if I was wearing something more fitted. If you were eyeing the translucent white version for bad weather racing, I'd suggest looking elsewhere.
For general use this isn't really an issue, if you don't mind the noise at any rate. I found it was comfortable to wear and great to have when the temperature dropped or the wind picked up mid-ride. Vents across the top of the back help with comfort too, as the breathability is not the highest. Additional vents under the armpits help prevent sweat build-up, but do contribute to the wind-resistance too. Generally, though, it feels a lot nicer than a hard-shell if you're only wearing short sleeves underneath, at least until it gets wet.
There are a couple of small reflective details on the outside, on the front of the left shoulder, beside the bottom of the zip, and on the rear of the left hip, obviously positioned mostly with continental rather than UK roads in mind. It would be nice to have a bit more on this front to help night-time visibility. It's a nice surprise to see a YKK-branded camlock zip with a garage flap at this price. The stitching inside the jacket is really basic, however, with loose looping thread which wouldn't cope well at all if introduced to some velcro.
This wind jacket from Decathlon is a good value and ultra-compact emergency layer that does a decent job of keeping wind and light rain at bay. The fit and some of the construction is pretty basic, and it's not ideal for riding fast as it gets very flappy, but it does an honest job at a very low price. I wouldn't set out on a ride wearing this (as I've other, better fitting and more technical jackets) but more than once I've been glad to have it in my bag or pocket when the weather turned.
Basic but effective wind-proof layer, best for upright riding positions; good value
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road.cc test report
Make and model: BTwin 700 UltraLight Wind Jacket
Size tested: Large High Vis
Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Regular cycling in spring and autumn when the weather is changeable (wind, light rain, etc.). Featherweight, windproof, fits in your hand
Tell us some more about the technical aspects of the product?
Ultralight and windproof Biosphere fabric.
Lightweight - 91 g in size L
Very compact. Fits in the palm of your hand when folded. Comes with carry pouch.
Water repellence - Light drizzle won't penetrate it
Guarantee : 2 Years
Mostly pretty good, especially given the price. Fabric is quite pleasant, but some concerns over the stitching.
Blocks wind effectively and offers some defence against light rain showers. Doesn't fit well for riding on bikes with drop bars, so best for casual flat-bar riding. Pretty un-aerodynamic.
Fabric is surprisingly tough - I was less convinced by the stitching.
Very lightweight indeed.
Pretty comfortable in use - works very well with a long-sleeve layer underneath, but is comfortable even over a short-sleeve jersey.
Cheap as chips.
Tell us how the product performed overall when used for its designed purpose
This is an effective emergency layer and works well to keep body heat in when the wind is cold. The fit makes it unsuitable for fast riding on drop-bar bikes, however, so it works best around town on a more upright bike.
Tell us what you particularly liked about the product
How light and stowable it was, while still offering worthwhile protection.
Tell us what you particularly disliked about the product
That it didn't fit me properly when riding on the drops or the hoods.
Did you enjoy using the product? Yes.
Would you consider buying the product? Maybe.
Would you recommend the product to a friend? Yes.
About the tester
Age: 36 Height: 190cm Weight: 78kg
I usually ride: Boardman CX team for the daily commute My best bike is: Rose Xeon CRS
I've been riding for: Over 20 years I ride: Most days I would class myself as: Expert
I regularly do the following types of riding: road racing, time trialling, cyclo cross, commuting, touring, club rides, sportives, general fitness riding, fixed/singlespeed, mtb,
Jez spends his days making robots that drive cars but is happiest when on two wheels. His roots are in mountain biking but he spends more time nowadays on the road, occasionally racing but more often just riding.