Ixion FAQ

KEVLAR® FAQ

A passing Hippie asked me: "Would you care to do me a paragraph or 2 for the FAQ on the delights of Kevlar(r) shirts and gloves?". Initially, I told the scrounging bastard to piss off and get a job, but in the end I acquiesced, not least because he pointed out that he had a job and that I did not.

I am somewhat of an advocate for "non-leather" motorcycle clothing. Not that I have anything against leather, I own (counts) three full race suits and four leather jackets. But it's just about the oldest fabric we use and, as a quondam Materials Scientist, I think that modern textiles can work better than a cow's backside in some motorcycling contexts. And they should be more predictable than leather, which is variable in quality, even in a single sheet.

Why is this?

Dr. Rod Woods
A clothing scientist and motorcyclist who got involved in the development of the CE standard for motorcycle protective equipment. I've attended some of Dr. Woods' talks and chatted with him on occasion. His statistical analysis of motorcyclists' injuries is the standard work for anyone thinking about what to wear on a motorcycle.

[Without digressing too far and going from memory, this says that injuries - now helmets are a given - get worse the further down the body you go, if you look at a picture of a human being standing upright, arms by their sides. So ankles need protection more than knees, hands need it as much as hips and shoulders are relatively unimportant - mainly because collarbones are "nature's crumple zone" and break anyway!]

Dr. Woods wears a Kevlar® suit of his own design, with the body armour which he designed and patented. He wears conventional knitted Kevlar® "glass handling" gloves and a pair of old paratrooper boots - because they are waterproof and very, very stiff.

So what is this wonder material?
KEVLAR® comes from DuPont and is 5 times stronger than steel on an equal weight basis, yet, at the same time, is lightweight, flexible and comfortable. It is also a unique yellow colour and very difficult to dye to other colours, so you can usually see when Kevlar® has been used in a garment.

Two research scientists, Stephanie Kwolek and Herbert Blades, working in a corporate lab created this remarkable aramid fibre in 1965. Fibres of KEVLAR® consist of long molecular chains produced from poly-paraphenylene terephthalamide. The chains are highly oriented with strong interchain bonding which result in a unique combination of properties: Because of the superior protection it provides, KEVLAR® brand fibre quickly became the technology of choice for bullet-resistant vests. Police officers have relied on the KEVLAR® brand for more than 25 years.

KEVLAR® para-aramid fibre possesses a remarkable combination of properties:
* High Tensile Strength at Low Weight
* Low Elongation to Break High Modulus (Structural Rigidity)
* Low Electrical Conductivity
* High Chemical Resistance
* Low Thermal Shrinkage
* High Toughness (Work-To-Break)
* Excellent Dimensional Stability
* High Cut Resistance
* Flame Resistant, Self-Extinguishing

Applications of KEVLAR®:
* Small-diameter, lightweight ropes that hold 22,000 pounds and help moor the largest U.S. Navy vessels
* Shrapnel-resistant shielding in jet aircraft engines that will protect passengers in case an explosion occurs
* Gloves that protect hands and fingers against cuts, slashes and other injuries that often occur in glass and sheet metal factories
* Kayaks that provide better impact resistance with no extra weight
* And - of course - motorcycle protective gear.

Performance Bikes Magazine
When Performance Bikes' John Robinson tested unlined (summer) leather gloves, Dr. Woods persuaded him to use a pair of knitted Kevlar "glass handling" gloves as a 'control'. They tested the gloves by placing a standard sized wooden puck in each glove (palm down, as Dr. Wood's research shows that people slide with palms down). The glove was then pressed on a linishing machine [a giant belt sander] with a set force and the distance: time to wear through was measured.

The Kevlar® won, of course. In fact, it beat the best unlined gloves by a factor of three: you would slide three times as far before the road hurt your hands in Kevlar® gloves than you would in the best leather gloves. As confirmation, CPPT (no, I don't know who these people are!) data shows that Kevlar® is up to five times more cut resistant than leather, which is why it is used in the glass industry.

And the best leather gloves cost from 6 to ten times what the Kevlar® gloves cost. Even if you're wealthy, you probably don't replace your expensive summer gloves each year. But sweat etc. will weaken the leather and the stitching of the leather gloves - whereas (see above)Kevlar® is almost inert. The PB tests were on new gloves - a more realistic test might have included gloves which had been worn for a few months .. in which case the Kevlar® would probably have won by an even fatter margin than "three times better than leather".

Kevlar® is NOT the solution in all situations.
Why don't Riders' Warehouse use Kevlar® in their excellent and unreservedly recommended Roadcrafter suits? Their website (www.aerostich.com) has the following:

"We still choose Cordura®, not Kevlar®. Here's why: Its advantages just don't make up for its disadvantages.

In pure, undiluted form, Kevlar® is lighter than nylon and has greater tensile strength. It won't melt like nylon a fter touching a hot muffler (or from the friction-generated heat of a high speed slide on hot pavement). Unfortunately, it's expensive and difficult to work with, which limits design and construction possibilities. And believe it or not, pure Kevlar® fabric actually is much less abrasion-resistant than Cordura nylon. Kevlar® fibres have far less elasticity than Cordura® nylon fibres, a crucial handicap in a crash. Even the smoothest pavements have a rough aggregate surface that causes abrasive pulling. Nylon's stretchy fibres will elongate, ride over the surface irregularities, then snap back into the weave (like a tree bending in a strong wind), but Kevlar® fibres quickly reach their tensile limit and snap.

To solve these problems, manufacturers blend Kevlar® with Lycra® and nylon. In this blend, "Kevlar®" is only about one third actual Kevlar®. This creates problems. Because of the additional nylon and Lycra®, much of its slight weight advantage over Cordura® is lost. It also loses some of its fire-resistant qualities. The blended Kevlar® fabric may burn or melt (just like nylon) when it comes in contact with a flame, hot component, or high frictional heat.

Some Kevlar® suits may provide good crash performance because they are specifically designed for sanctioned competitive road racing. Roadcrafter suits aren't, but fortunately they're designed for everything else, including abrasion resistance at highway speeds.

We've tested (and will continue to test) Cordura® nylon against the alternatives. Its superior comfort, easy workability and excellent abrasion resistance make it our choice for quality, versatile, high performance riders' clothing. You've got a choice between the Roadcrafter and its proven record of outstanding abrasion performance, and something that costs more and delivers less. Guess what we recommend."

The fabric to which Riders' Warehouse appear to be referring is Schoeller K-protek. You'll find this in the knee and groin panels of some leathers and on the elbows and shoulders of the Scott "Road" jackets. It is not Kevlar®, it is (as Riders' Warehouse correctly say) a blend of Kevlar® with Lycra® etc. It has its advantages, but it is NOT the best way to use Kevlar®.

Other Advantages
Warm. Have you ever worn a string vest: Warm despite the holes, isn't it? The same is true of knitted Kevlar® gloves. They are surprisingly warm on a 'bike. I wear mine quite early in the spring and quite late in the autumn. And, if the weather is really foul (e.g.: snow!), I'll wear waterproof mittens with the Kevlar® under them, in preference to my winter gauntlets.

Dry quickly. Kevlar® fibres do not absorb water. It comes in through the holes in the knit or the weave, but the fabric is impervious. So the gloves dry in instants, once the rain stops. If you've ever met a summer downpour in unlined leather gloves (and had the dye leach out onto your hands, as like as not) you might find Kevlar® a better bet.

Washable. Do your sweaty gloves offend people and attract dogs? My (three year old) Kevlar® gloves are clean, because they are machine washable. I use Kevlar® for off road riding, because moto-x gloves are usually of dire quality and because you can wash the mud out of them.

Fireproof. I bought (mail order) two sets of "double layer" Kevlar® gloves. They turned out to be too thick for comfortable 'bike use, so I gave one pair to a pal (they only cost about 15 pounds a pair) and kept the other set for welding gloves. Said pal runs a training centre and has BIG barbeques every week through the summer. Not only can you lift the grill off the - half oil drum - barbie while wearing these gloves to add more charcoal; you can stir the burning coals with your gloved hand!

Personal Choice
I have four Kevlar® motorcycling garments:

* Medium weight Kevlar® knitted gloves from ARCO Safety Supplies. Yellow. Cost under ten pounds a pair. I've added Velcro(tm) wrist straps to stop them coming off in a slide. Best buy! ARCO has branches all over the UK, so you can buy face-to-face, which allows you to try their three or four different types of Kevlar® gloves first. (see below for product details)

* Dragin' Jeans' knitted Kevlar® gloves. Cost about 15 pounds a pair. Come in black (which is why I got them) and with the Velcro(tm) already on. Not worth the premium, unless you can't face yellow gloves or adding wrist straps. Don't bother.

* Dragin' Jeans' knitted Kevlar® sweatshirt. Designed for riding in Australia (where leathers can be too hot!). I wear this under a denim jacket or rugby shirt for rides in hot weather. Or you could wear it under a waterproof jacket, for added protection. Sadly, this top was expensive (about 60 pounds) as it's made for the relatively small motorcycle market. The glass handling gloves are cheap because the glass industry buys millions of pairs a year. It's black, but Kevlar® does not dye well and it fades very quickly. If you will ever (e.g.) ride across the Karoo desert in 45 decrees of heat, this is a must. If you'd never, ever ride without a heavy jacket, it's not worth it.

* Hood Jeans' armoured / Kevlar® lined jeans. Feel like jeans (especially if you fit Heine Gericke's Hiprotek armour in place of the bulky armour they suggest), but protect like GOOD leathers in a slide. Let me stress that bit: these jeans have acres of Kevlar® in them, so they will be VERY tough in a slide. Probably far tougher than lightweight/ summer-weight leathers. I got a black pair (they do blue denim or cargo pants as alternatives) for around seventy pounds, inc. the armour and having them hemmed to length. Best buy!

Future
Draggin' Jeans say they will sell Kevlar® long johns ... one day. These would allow you to wear any pair of trousers on a 'bike and still be "reasonably" safe.

One day - we hope - Dr. Rod Woods' suit made of Kevlar® and other CLEVER MATERIALS may hit the market. It won't be cheap - probably 500 quid plus - but it would replace leathers, waterproofs ... everything in your 'biking wardrobe. And it will be light, comfy to wear, pack away small (have you ever tried to pack leathers??) and be machine washable. We can hope.

All the facts and wisdom are other peoples', all the errors are mine. I have no commercial relationship, other than as satisfied customer, with these firms.

mark@markhodson.com

This article may be freely reproduced providing it is textually unchanged and this footer remains appended.

From Gene Rankin, obYank:

[snipped: tons of good stuff re: Kevlar] Most of which I've said before, having used the material since 1974 as sailcloth (and for the fastest sailing hat you'll ever see), back when Dupont called it Fiber B. However...

>When Performance Bikes' John Robinson tested unlined (summer) leather
>gloves, Dr. Woods persuaded him to use a pair of knitted Kevlar
>"glass handling" gloves as a 'control'. They tested the gloves by
>placing a standard sized wooden puck in each glove (palm down, as Dr.
>Wood's research shows that people slide with palms down). The glove
>was then pressed on a linishing machine [a giant belt sander] with a
>set force and the distance: time to wear through was measured.

>The Kevlar(r) won, of course. In fact, it beat the best unlined
>gloves by a factor of three: you would slide three times as far
>before the road hurt your hands in Kevlar(r) gloves than you would in
>the best leather gloves.

I have always taken as gospel the poor abrasion resistance of Kevlar, know from first-hand the tensile strength and the catastrophic nature of the fiber's failure, and also know how hard it is to cut and sew (I destroyed a couple pair of scissors and several of my then-wife's sewing machine needles). The experiment reported above, however, tells a very different story. Is Dr. Woods' stuff 100% Kevlar? If so, where does it come from?

As confirmation, CPPT (no, I don't know who these people are!) data shows that Kevlar(r) is up to five times more cut resistant than leather, which is why it is used in the glass industry.

That's because cutting is a different action to abrading (there'll be an Andy LePugh along in a bit to say why - or why not). Damned few things cut Kevlar before going dull. I have a spiffy Spyderco Mariner stainless rigging knife which does the job quite nicely (and which looks scary as hell, all serrated).

ObYank: Gene Rankin / Madison, WI / USA - please CC

From Andy Woodward

> I have always taken as gospel the poor abrasion resistance of Kevlar,
> know from first-hand the tensile strength and the catastrophic nature
> of the fiber's failure, and also know how hard it is to cut and sew (I
> destroyed a couple pair of scissors and several of my then-wife's
> sewing machine needles).  The experiment reported above, however,
> tells a very different story.  Is Dr. Woods' stuff 100% Kevlar?  If
> so, where does it come form?

It appears that the knitted construction is paramount. It allows the abrasion task to become a tensile task - fibres grab and bounce, grab, bounce, grab....... A cloth weave simply rips the fibres out when they grab and hte cloth explodes. But a knit uses one fiber and so it much more robust, kevlar being VERY good at tensile tasks.

Chainsaw type kelvar, where the fibres are in a random loose mat are crap in bike crashes. Kevlar cloth is better but mostly crap. But the knitted gloves beat leathers into a cocked hat again and again in tests. The reason I bought a Draggin K-shirt was that it is knitted. The reason I have not bought anything like Hoods are that they use a cloth weave.

I repeatedly pestered Draggin about their "imminently forthcoming" knitted longjohns over a year ago. There's still no sign of the bloody things - I'll have a pair the very day they are released onto the market (if ever...)

Note also that you can get double thickness knitted forearm protectors - sew up the ends and these make very nice crashproof socks.

And more from Hoddy

>again in tests. The reason I bought a Draggin K-shirt was that it is 
>knitted. The reason I have not bought anything like Hoods  are that 
>they use a cloth weave.

Knitted is best, for sure.

But the weave in the Hoods is good and well protected by stout denim, so it passes the "drag it along with a sandbag on top of it" test.

Far, far better than the old Shoshonis (two layers of denim and a bit of foam rubber), at the very least. And more Kevlar than Gialli bother with.

Hoddy

Following a browse of the ARCO Safety Supplies website I had the following conversation with Mr Hodson -

> when browsing the arco.co.uk site you recommended, a search in gloves for
> "kevlar" returned 13 results. Which ones did you like? Can you remember
> the code#? They have Ansell Lightweight Neptune Kevlar(R) Gloves NK11S
> Medium at less than GBP5.00 per pair, too thin for M'cycling??

<FX>Picks up paper ARCO cat'n'dog.</fx>
<FX> spends 5 minutes engrossed in the "cold store" gloves </fx>
<Thinks>Hmmm! Winter's coming!</T>

Comacier Kevlar M/W score 2.3.4.X - £5.59
or the Neptune M/W (not the L/W!) score 1.3.4.X and are £6.36
or the Neptune H/W at 2.3.4.X - cost £8.52
The Neptune EH/W are too thick.
The Comacier are light and cheap and score very well.
I guess those costs are ex-VAT.

> Orders less than GBP75.00 incur a GBP6.00 handling charge.

I go to ARCO in Orpington and buy them F-F. No charge and you can scavange the bargain bins.

Hoddy

This page last updated 22/09/02

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