NEED TO KNOW

Insider info on the tech behind a winter bike jacket

COMPLEXITY 01

Being a bike jacket is a complex job. It needs to keep out the cold without making you overheat, and it should prevent rain from getting in but not stop sweat evaporating out. It’s a tricky proposition, even with the advent of today’s advanced fabrics. Suffice to say, coming up with a suitable solution means a winter bike jacket is as high-tech as any other cycling clothing item. Scratch beneath the surface and you quickly find yourself in a world of hydrophilic polyurethane coatings and ePTFE membranes with billions of micropores per square inch.

But why do they need to be so complex when all they’re doing is being a barrier between you and the elements? The answer to that is you, or more specifically, the heat and sweat you generate while riding. Cold and wet weather can not only make you miserable, it can affect your performance. But so can getting too hot and soaking in sweat, which means a cycling jacket and the fabrics it’s made from need to work like an elaborate one-way system. They need to be porous and gas permeable from the inside out but non-porous and impermeable from the outside in.

BREATH ABILITY 02

Waterproofing and water-resistant treatments have often been the enemy of breathability in a cycling jacket, but that’s improved recently and bike jackets are no longer the glorified bin bags of old. But where have the technological leaps been made?

“This is mainly through the addition of the DWR (durable water-repellent coating), which allows the surface fabric and the membrane to perform at their best by not letting the rain water ‘wet out’ the jacket and clog up the air permeability,” states Amy Spencer, design and development manager for Altura. “This membrane also has a breathability rating

– how much air it will let escape. This is given a rating of 5k, 10k, 15k or 20k [with 20K being the most effective]. To ensure the breathability of the membrane performs efficiently, we also add a DWR to the face side (outside) of the fabric which helps the rain droplets bead, and fall from the jacket so they don’t penetrate the top layer of fabric and stop the jacket being as breathable.”

STORAGE 03

Cash, card, keys, phone, jelly babies, peanut butter sandwich, multi-tool, spare pump, banana, flapjack… if you’re anything like us, your pockets will be bulging when you exit the house. Happily, most bike jackets can accommodate moving buffets, but increasingly important for us is a zipped and waterproof pocket that’s big enough to stash a smart phone.

A waterproof phone case is a smart addition to your bike-jacket purchase for added protection and ease of mind, but it’s worth messaging the brand’s online customer support if you’re worried that your mobile – hello the iPhone 12 Pro Max – may be too big as a pocket companion.

WATERPROOFING 04

The key remits of the softshell jackets on test are to provide warmth and windproofing, but there’s also water-resistant tech at play. Most of the 12 jackets will survive a shower (see more in the specific reviews),

Preventing overheating and rain, allowing sweat to evaporate... a jacket is high-tech clothing

but they lack the fully waterproofing capabilities of a hardshell jacket. Just where does the extra rain-thwarting element come from in the more spring and autumn-friendly hardshell?

“For a jacket to be fully waterproof, the fabric must have a membrane, described as a 2; 2.5; or 3-layer construction,” adds Spencer. “The membrane makes the jacket waterproof by creating a barrier under the surface fabric. This is the part of the fabric that determines the hydrostatichead rating (waterproof rating) of 5k, 10k, 15k or 20k [as with the breathability rating, the higher the number, the more effective the waterproofing]. Waterproof jackets are also made like a non-waterproof jacket by stitching panels together. Essentially,a needle punches holes in the membrane, which then makes that area of the fabric not fully waterproof. So we add taping to the inside of the jacket to seal these holes and make the garment fully waterproof.”

TESTING 05

The prices of the jackets on test here range from £100 to the topend £270 offerings, with that RRP covering the R&D, material costs and also a lengthy testing process before the jacket hits the retail depots. Spencer expands on the demands that brands place on the constructions before its retail thumbs-up: “Once a fabric is selected, it’s tested in a lab to determine its waterproof, breathability, and spray ratings. Once the jacket is produced, it’s tested again on the seams for the same performance requirements to ensure the seams are at the same level as the main fabric. We also have our fabrics tested for colour fastness to ensure the colours don’t migrate. We then test each item to determine the fibre composition, and do wash testing to ensure the jacket stays as good as new, wash after wash. For certain jackets, we also perform a Martindale test that determines the durability of the fabric.

“Although lab tests are a great source of information to determine the performance of the fabric, we also test our jackets in real-world conditions. Lastly, we have a fantastic group of people who test our products to destruction – they’re out riding in our kit in all weathers to provide us with feedback, not only on the performance of the jacket, but also the ease of use, the comfort and the fit.”

LIFE CYCLE 06

Following the recommended washing instructions will not only preserve your jacket’s lifespan and save you pennies, but will help lower your ecological footprint. That heightened environmental awareness is shown in the lack of plastic packaging many of the jackets here arrived in, and also in some of the material choices on display. It’s a movement that’ll only intensify, believes Spencer.

“Within five years, I’d like to see more fabrics that are sustainably sourced without compromising on the level of performance. As a rider, you need to feel comfortable that you’re protected from the elements, as well as buying a product where its whole life cycle has been considered.”

A zipped waterproof pocket that’s big enough to stash a smart phone is important

“As a rider, you need to be comfortable that you’re protected from the elements”