Simply known as ‘Kevlar jeans’ to most bikers, this sweeping naming convention hides a vast array of technical innovation and wildly different construction methods which all achieve the same thing: combining protection from impact and abrasion with the casual looks of the world’s favourite cotton product.
Technically, Kevlar jeans are not Kevlar jeans at all: most commonly they are Kevlar-lined denim jeans, and quite often the Kevlar is not Kevlar but the generic version called Aramid. So, what’s it all about?
WHAT IS KEVLAR?
Kevlar is a trademark of the fibre specialists DuPont; it is their version of the aramid fibre, milled into the Kevlar thread, whose singular quality is its strength. The thread is turned into Kevlar fabrics that protect mankind from all sorts of ills, from abrasion protection in motorcycle jeans to bullet-proof vests.
What makes a Kevlar-based fabric special is not so much that DuPont have fundamentally reengineered the aramid fibre, but that DuPont are specialists in their field: which means that abrasion resistant fabric made from the Kevlar fibre is of consistently high quality. To ensure this is still the case in the end product, DuPont control the production chain from yarn to final garment.
DOES IT MATTER IF IT’S NOT KEVLAR?
The quick answer is: ‘no’. The longer answer is: ”it depends’. The aramid fibre is the generic version of DuPont Kevlar and has the same qualities, providing it was manufactured correctly and knitted or woven correctly into fabric. And there is the reason as to why it depends: in order to reduce production costs, some abrasion-resistant lining fabrics contain a lower proportion of aramid fibres. Quite often they are dyed in that familiar yellow colour that marks out Kevlar fabrics, so they look the part. But when the denim hits the road, so to speak, the reduced aramid content of the fabric means far, far reduced abrasion resistance. When it comes to protective qualities in motorcycle clothing, you really do get what you pay for. If you trust the brand and its manufacturing quality, go for it; otherwise a lower price may well result in lower protection.
HOW DOES THE ABRASION RESISTANCE WORK?
Simplistically, Kevlar fibres and therefore yarn has a huge strength advantage over cotton and other man-made fibres. Therefore fabric made from these fibres will hold its own for much longer than denim-based fabric. But there’s more to it than that: the most effective construction is a knitted fabric, which provides additional ‘give’ and where the loops of the knit compact to make a thicker fabric at the point of impact. That is one of the reasons why Kevlar jeans with proper knitted Kevlar fabric panels also are warm to wear: those knitted panels are very similar to terry towelling in construction, so no wonder we get hot. On the other hand, some brands offer jeans with woven aramid linings. Woven fabrics are much better for burst strength, as perhaps required in a bullet-proof vest, but the abrasion resistance is very poor and you’re better off staying away from those.
And, there has been some real innovation:
REV’IT!’S PWR SHIELD FABRIC
The designers at REV’IT! weren’t content creating protective motorcycle jeans that had the same downsides as existing Kevlar lined jeans. As a consequence, they developed, under their own brand name, PWR Shield, an aramid fabric that is cooler to wear and still highly protective. It is constructed like a sandwich, with two layers to allow more air flow. On impact, the two layers compact together to form a thick Kevlar lining that withstands a great amount of abrasion. Clever!
REV’IT! AND ROUTE ONE’S CORDURA DENIMS
In traditional motorcycle jeans, only the areas backed by the Kevlar lining are actually abrasion protected. That leaves the majority of the garment no more protected than your regular Levi’s jeans. With that in mind, REV’IT! developed denim fabrics that contained Cordura, without feeling any different than normal cotton denim. The Cordura component of course meant that the whole jeans are now more abrasion-resistant, not just the areas backed with Kevlar panels. Other innovative brands like Route One have followed suit, such as the Route One Selvage jeans.
COTTON KEVLAR MIXES
And, to develop abrasion-resistant cotton denim material further, a cotton-Kevlar mix denim has been developed. While not totally new, only very recently has that fabric become wearable and lighter in weight. One of the best examples is being used, for instance, in jeans like the Held Barrier jean, which is also a waterproof jean.
What’s the upshot then? More than ever before there is a large choice of protective motorcycle jeans, and in amongst that choice there with the perfect jean with your name on it. REV’IT! offers a vast range of urban and highly functional styles, from skinny fits to loose fits. If designer names are your bag, Dainese’s jeans are designed by Diesel. Waterproof jeans are now available from REV’IT!, Held and Route One to name a few.