Make
Motorcycle Riding Safety Your Top Priority
Operating
a motorcycle takes different skills than driving a car; however,
the laws of the road apply to every driver just the same. A
combination of consistent education, regard for traffic laws and
basic common sense can go a long way in helping reduce the
amount of fatalities involved in motorcycle accidents on a
yearly basis.
Here
is a checklist that every motorcycle rider should follow:
-
Always
wear a helmet with a face shield or protective eyewear
— Wearing a helmet is the best way to protect against
severe head injuries. A motorcycle rider not wearing a
helmet is five times more likely to sustain a critical head
injury.
-
Wear
appropriate gear — Make sure to wear protective
gear and clothing that will minimize the amount of injuries
in case of an accident or a skid. Wearing leather clothing,
boots with nonskid soles, and gloves can protect your body
from severe injuries. Consider attaching reflective tape to
your clothing to make it easier for other drivers to see
you.

-
Follow
traffic rules — Obey the speed limit; the faster
you go the longer it will take you to stop. Be aware of
local traffic laws and rules of the road.
-
Ride
defensively — Don’t assume that a driver can
see you, as nearly two-thirds of all motorcycle accidents
are caused by a driver violating a rider’s right of way.
You should always ride with your headlights on; stay out of
a driver’s blind spot; signal well in advance of any
change in direction; and watch for turning vehicles.
-
Keep
your riding skills honed through education —
Complete a formal riding education program, get licensed and
take riding courses from time to time to develop riding
techniques and to sharpen your street-riding strategies.
-
Be
awake and ride sober — Don’t drink and ride,
you could cause harm to yourself and others. Additionally,
fatigue and drowsiness can impair your ability to react, so
make sure that you are well rested when you hit the road.
Preparing
to Ride
Making
sure that your motorcycle is fit for the road is just as
important as practicing safe riding. Should something be wrong
with your motorcycle, it will be in your best interest to find
out prior to hitting the road. To make sure that your motorcycle
is in good working order, check the following:
-
Tires
— check for any cracks or bulges, or signs of wear in the
treads. Low tire pressure or any defects could cause a
blowout.
-
Under
the motorcycle — Look for signs of oil or gas
leaks.
-
Headlight,
taillight and signals — Test for high and low
beams. Make sure that all lights are functioning.
-
Hydraulic
and Coolant fluids — Level should be checked
weekly.
Once
you've mounted the motorcycle, complete the following checks:
-
Clutch
and throttle - Make sure they are working smoothly.
Throttle should snap back when released.
-
Mirrors
— Clean and adjust all mirrors to ensure sharpest viewing.
-
Brakes
— Test front and rear brakes. Each brake should feel firm
and hold the motorcycle still when fully applied.
-
Horn
— Test the horn
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How
good is your helmet? Will it actually protect your brain in your
next crash?
These seem like easy questions, ones you probably think you can
answer by reciting the lofty standards your helmet meets and the
lofty price you might have paid for it. But the real answers, as
you are about to see, are anything but easy.
There's a fundamental debate raging in the motorcycle helmet
industry. In a fiberglass-reinforced, expanded-polystyrene
nutshell, it's a debate about how strong and how stiff a helmet
should be to provide the best possible protection.
Why the debate? Because if a helmet is too
stiff it can be less able to prevent brain injury in the kinds
of crashes you're most likely to have. And if it's too soft, it
might not protect you in a violent, high-energy crash. What's
just right? Well, that's why it's called a debate. If you knew
what your head was going to hit and how hard, you could choose
the perfect helmet for that crash. But crashes are accidents. So
you have to guess.
To understand how a helmet protects—or doesn't protect—your
brain, it helps to appreciate just how fragile that organ
actually is. The consistency of thhe human brain is like warm
Jello. It's so gooey that when pathologists remove a brain from
a cadaver, they have to use a kind of cheesecloth hammock to
hold it together as it comes out of the skull.
Your brain basically floats inside your skull,
within a bath of cervical-spinal fluid and a protective cocoon
called the dura. But when your skull stops suddenly—as it does
when it hits something hard—the brain keeps going, as Sir
Isaac Newton predicted. Then it has its own collision with the
inside of the skull. If that collision is too severe, the brain
can sustain any number of injuries, from shearing of the brain
tissue to bleeding in the brain, or between the brain and the
dura, or between the dura and the skull. And after your brain is
injured, even more damage can occur. When the brain is bashed or
injured internally, bleeding and inflammation make it swell.
When your brain swells inside the skull, there's no place for
that extra volume to go. So it presses harder against the inside
of the skull and tries to squeeze through any opening, bulging
out of your eye sockets and oozing down the base of the skull.
As it squeezes, more damage is done to some very vital regions.
None of this is good.
Helmet designers have devised a number
of different liner designs to meet the different
standards. The Vemar VSR uses stiffer EPS than most,
but has channels molded in to soften the assembly (to
ECE specs) and enhance cooling.
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To prevent all that ugly stuff from happening,
we wear helmets. Modern, full-face helmets, if we have enough
brains to protect, that is.
A motorcycle helmet has two major parts: the outer shell and the
energy-absorbing inner liner. The inner lining is made of
expanded polystyrene or EPS, the same stuff used in beer
coolers, foam coffee cups, and packing material. Outer shells
come in two basic flavors: a resin/fiber composite, such as
fiberglass, carbon fiber and Kevlar, or a molded thermoplastic
such as ABS or polycarbonate, the same basic stuff used in face
shields and F-16 canopies.
The shell is there for a number of reasons. First, it's supposed
to protect against pointy things trying to penetrate the
EPS—though that almost never happens in a real accident.
Second, the shell protects against abrasion, which is a good
thing when you're sliding into the chicane at Daytona. Third, it
gives Troy Lee a nice, smooth surface to paint dragons on.
Riders—and helmet marketers—pay a lot of attention to the
outer shell and its material. But the part of the helmet that
absorbs most of the energy in a crash is actually the inner
liner.
When the helmet hits the road or a curb, the outer shell stops
instantly. Inside, your head keeps going until it collides with
the liner. When this happens, the liner's job is to bring the
head to a gentle stop—if you want your brain to keep working
like it does now, that is.
The great thing about EPS is that as it crushes, it absorbs lots
of energy at a predictable rate. It doesn't store energy and
rebound like a spring, which would be a bad thing because your
head would bounce back up, shaking your brain not just once, but
twice. EPS actually absorbs the kinetic energy of your moving
head, creating a very small amount of heat as the foam
collapses.
The Schuberth S1 uses five separate
foam parts glued together to meet the ECE standard.
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The helmet's shell also absorbs energy as it
flexes in the case of a polycarbonate helmet, or flexes, crushes
and delaminates in the case of a fiberglass composite helmet.
To minimize the G-forces on your soft, gushy brain as it stops,
you want to slow your head down over as great a distance as
possible. So the perfect helmet would be huge, with 6 inches or
mosre of soft, fluffy EPS cradling your precious head like a
mint on a pillow.
Problem is, nobody wants a 2-foot-wide helmet, though it might
come in handly if you were auditioning for a Jack in the Box
commercial. So helmet designers have pared down the thickness of
the foam, using denser, stiffer EPS to make up the difference.
This increases the G-loading on your brain in a crash, of
course. And the fine points of how many Gs a helmet transmits to
the head, for how long, and in what kind of a crash, are the
variables that make the helmet-standard debate so gosh darn fun.
The helmets are mounted on a 5-kilo (11
pound) magnesium headform and then dropped from a
controlled height onto a variety of test anvils to
simulate crash impacts on various surfaces and shapes.
In the real world, your helmet actually hits flat
pavement more than 85 percent of the time.
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Standardized Standards
To make buying a helmet in the U.S as confusing as possible,
there are at least four standards a street motorcycle helmet can
meet. The price of entry is the DOT standard, called FMVSS 218,
that every street helmet sold here is legally required to pass.
There is the European standard, called ECE 22-05, accepted by
more than 50 countries. There's the BSI 6658 Type A standard
from Britain. And lastly the Snell M2000/M2005 standard, a
voluntary, private standard used primarily in the U.S. So every
helmet for street use here must meet the DOT standard, and might
or might not meet one of the others. Just by looking at the
published requirements for each standard, you would guess a
DOT-only helmet would be designed to be the softest, with an ECE
helmet very close, then a BSI helmet, and then a Snell helmet.
Because there are few human volunteers for high-impact helmet
testing—and because they would be a little confused after a
hard day of 200-G impacts—it's done on a test rig.
The helmets are dropped, using gravity to accelerate the helmet
to a given speed before it smashes onto a test anvil bolted to
the floor. By varying the drop height and the weight of the
magnesium headform inside the helmet, the energy level of the
test can be easily varied and precisely repeated. As the helmet/headform
falls it is guided by either a steel track or a pair of steel
cables. That guiding system adds friction to slow the fall
slightly, so the test technician corrects for this by raising
the initial drop height accordingly.
The headform has an accelerometer inside that precisely records
the force the headform receives, showing how many Gs the
headform took as it stopped and for how long.
If you test a bunch of helmets under the same conditions, you
can get a good idea of how well each one absorbs a particular
hit. And it's important to understand that as in lap times, golf
scores and marriages, a lower number is always better when we're
talking about your head receiving extreme G forces.
All the Snell/DOT helmets we examined
use a dual-density foam liner. The upper cap of foam
on this Scorpion liner is softer to compensate for the
extra stiffness of the spherical upper shell area.
Some manufacturers, including Arai and HJC, use a
one-piece liner with two different densities molded
together.
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On The Highway To Snell
On the stiff, tough-guy side of this debate is the voluntary
Snell M2000/M2005 standard, which dictates each helmet be able
to withstand some tough, very high-energy impacts.
The Snell Memorial Foundation is a private, not-for-profit
organization dedicated to "research, education, testing and
development of helmet safety standards."
If you think moving quickly over the surface of the planet is
fun and you enjoy using your brain, you should be grateful to
the Snell Memorial Foundation. The SMF has helped create
standards that have raised the bar in head protection in nearly
every pursuit in which humans hit their heads: bicycles, horse
riding, harness racing, karting, mopeds, skateboards,
rollerblades, recreational skiing, ski racing, ATV riding,
snowboarding, car racing and, of course, motorcycling.
But as helmet technology has improved and accident research has
accumulated, many head-injury experts feel the Snell M2000 and
M2005 standards are, to quote Dr. Harry Hurt of Hurt Report
fame, "a little bit excessive."
The killer—the hardest Snell test for a motorcycle helmet to
meet—is a two-strike test onto a hemispherical chunk of
stainless steel about the size of an orange. The first hit is at
an energy of 150 joules, which translates to dropping a 5-kilo
weight about 10 feet—an extremely high-energy impact. The next
hit, on the same spot, is set at 110 joules, or about an 8-foot
drop. To pass, the helmet is not allowed to transmit more than
300 Gs to the headform in either hit.
Tough tests such as this have driven helmet
development over the years. But do they have any practical
application on the street, where a hit as hard as the hardest
single Snell impact may only happen in 1 percent of actual
accidents? And where an impact as severe as the two-drop hemi
test happens just short of never?
Dr. Jim Newman, an actual rocket scientist and highly respected
head-impact expert—he was once a Snell Foundation
director—puts it this way: "If you want to create a
realistic helmet standard, you don't go bashing helmets onto
hemispherical steel balls. And you certainly don't do it twice.
"Over the last 30 years," continues Newman,
"we've come to the realization that people falling off
motorcycles hardly ever, ever hit their head in the same place
twice. So we have helmets that are designed to withstand two
hits at the same site. But in doing so, we have severely,
severely compromised their ability to take one hit and absorb
energy properly.
"The consequence is, when you have one hit at one site in
an accident situation, two things happen: One, you don't fully
utilize the energy-absorbing material that's available. And two,
you generate higher G loading on the head than you need to.
"What's happened to Snell over the years is that in order
to make what's perceived as a better helmet, they kept raising
the impact energy. What they should have been doing, in my view,
is lowering the allowable G force.
"In my opinion, Snell should keep a 10-foot drop [in its
testing]. But tell the manufacturers, 'OK, 300 Gs is not going
to cut it anymore. Next year you're going to have to get down to
250. And the next year, 200. And the year after that,
185.'"
The Brand Leading The Brand
"The Snell sticker," continued Newman, "has
become a marketing gimmick. By spending 60 cents [paid to the
Snell foundation], a manufacturer puts that sticker in his
helmet and he can increase the price by $30 or $40. Or even $60
or $100.
"Because there's this allure, this charisma, this image
associated with a Snell sticker that says, 'Hey, this is a
better helmet, and therefore must be worth a whole lot more
money.' And in spite of the very best intentions of everybody at
Snell, they did not have the field data [on actual accidents]
that we have now [when they devised the standard]. And although
that data has been around a long time, they have chosen, at this
point, not to take it into consideration."
The Z1R ZRP-1 uses a soft, one-piece
liner to soak up joule after joule of nasty impact
energy.
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"What should the [G] limit on helmets be?
Just as helmet designs should be rounder, smoother and safer,
they should also be softer, softer, softer. Because people are
wearing these so-called high-performance helmets and are getting
diffused [brain] injuries ... well, they're screwed up for life.
Taking 300 Gs is not a safe thing.
"We've got people that we've replicated helmet [impacts] on
that took 250, 230 Gs [in their accidents]. And they've got a
diffuse injury they're not gonna get rid of. The helmet has a
good whack on it, but so what? If they'd had a softer helmet
they'd have been better off."
How does the Snell Foundation respond to the criticism of
head-injury scientists from all over the world that the Snell
standards create helmets too stiff for optimum protection in the
great majority of accidents?
"The whole business of testing helmets is based on the
assumption that there is a threshold of injury," says Ed
Becker, executive director of the Snell Foundation. "And
that impact shocks below that threshold are going to be
non-injurious. "We're going with 300 Gs because we started
with 400 Gs back in the early days. And based on [George
Snively's, the founder of the SMF] testing, and information he'd
gotten from the British Standards Institute, 400 Gs seemed
reasonable back then. He revised it downward over the years,
largely because helmet standards were for healthy young men that
were driving race cars. But after motorcycling had taken up
those same helmets, he figured that not everybody involved in
motorcycling was going to be a young man. So he concluded from
work that he had done that the threshold of injury was above 400
Gs. But certainly below 600 Gs.
"The basis for the 300 G [limit in the Snell M2000
standard] is that the foundation is conservative. [The
directors] have not seen an indication that a [head injury]
threshold is below 300 Gs. If and when they do, they'll
certainly take it into account."
So nobody is being hurt by the added stiffness of a Snell
helmet, we asked.
"That's certainly our hope here," answered Becker.
"At this point I've got no reason to think anything
else."
European Style
The Snell Foundation may have no reason to think anything else.
But every scientist we spoke to, as well as the government
standards agencies of the United States and the 50 countries
that accept the ECE 22.05 standard, see things quite
differently.
The European Union recently released an extensive helmet study
called COST 327, which involved close study of 253 recent
motorcycle accidents in Germany, Finland and the U.K. This is
how they summarized the state of the helmet art after analyzing
the accidents and the damage done to the helmets and the people:
"Current designs are too stiff and too resilient, and
energy is absorbed efficiently only at values of HIC [Head
Injury Criteria: a measure of G force over time] well above
those which are survivable."
As we said, it's a lively debate.
If your brain is injured, swelling and
inflammation often occur. Because there's no extra
room inside your skull, your brain tries to squeeze
down through the hole in the base of the skull. This
creates pressure that injures the vital brain stem
even further, often destroying the parts that control
breathing and other basic body functions. If you're
hit very violently on the jaw, as in a head-on impact,
the force can be transmitted to the base of the skull,
which can fracture and sever your spine. It's a common
cause of death in helmeted motorcycle riders—and a
very good reason to wear a full-face helmet and insist
on thick EPS padding—not resilient foam—in the
helmet's chin bar. When your brain collides with the
inside of your skull, bony protrusions around your
eyes, sinuses and other areas can cause severe damage
to the brain. And if your head is twisted rapidly, the
brain can lag behind, causing tearing and serious
internal brain injury as it drags against the skull. A
helmet is the best way to avoid such unpleasantries.
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How Hurt is Hurt?
Doctors and head-injury researchers use a simplified rating of
injuries, called the Abbreviated Injury Scale, or AIS, to
describe how severely a patient is hurt when they come into a
trauma facility. AIS 1 means you've been barely injured. AIS 6
means you're dead, or sure to be dead very soon. Here's the
entire AIS scale:
AIS 1 = Minor
AIS 2 = Moderate
AIS 3 = Serious
AIS 4 = Severe
AIS 5 = Critical
AIS 6 = Unsurvivable
A patient's AIS score is determined separately for each
different section of the body. So you could have an AIS 4 injury
to your leg, an AIS 3 to your chest and an AIS 5 injury to your
head. And you'd be one hurtin' puppy. Newman is quoted in the
COST study on the impact levels likely to cause certain levels
of injury. Back in the '80s he stated that, as a rough
guideline, a peak linear impact—the kind we're measuring
here—of 200 to 250 Gs generally corresponds to a head injury
of AIS 4, or severe; that a 250 G to 300 G impact corresponds to
AIS 5, or critical; and that anything over 300 Gs corresponds to
AIS 6. That is, unsurvivable.
Newman isn't the only scientist who thinks getting hit with much
more than 200 Gs is a bad idea. In fact, researchers have pretty
much agreed on that for 50 years.
The Wayne State Tolerance Curve is the result of a pretty
gruesome series of experiments back in the '50s and '60s in
which dogs' brains were blasted with bursts of compressed air,
monkeys were bashed on the skull, and the heads of dead people
were dropped to see just how hard they could be hit before
big-time injury set in. This study's results were backed up by
the JARI Human Head Impact Tolerance Curve, published in '80 by
a Japanese group who did further unspeakable things to monkeys,
among other medically necessary atrocities.
The two tolerance curves agree on how many Gs you can apply to a
human head for how long before a concussion or other more
serious brain injury occurs. And the Wayne State Tolerance Curve
was instrumental in creating the DOT helmet standard, with its
relatively low G-force allowance.
According to both these curves, exposing a human head to a force
over 200 Gs for more than 2 milliseconds is what medical experts
refer to as "bad." Heads are different, of course.
Young, strong people can take more Gs than old, weak people.
Some prizefighters can take huge hits again and again and not
seem to suffer any ill effects other than a tendency to sell
hamburger cookers on late-night TV. And the impacts a particular
head has undergone in the past may make that head more
susceptible to injury.
Is an impact over the theoretical 200 G/2
millisecond threshold going to kill you? Probably not. Is it
going to hurt you? Depends on you, and how much over that
threshold your particular hit happens to be. But head injuries
short of death are no joke. Five million Americans suffer from
disabilities from what's called Traumatic Brain Injury—getting
hit too hard on the head. That's disabilities, meaning they
ain't the same as they used to be.
There's another important factor that comes into play when
discussing how hard a hit you should allow your brain to take:
the other injuries you'll probably get in a serious crash, and
how the effects of your injuries add up.
The likelihood of dying from a head injury goes up dramatically
if you have other major injuries as well. It also goes up with
age. Which means that a nice, easy AIS 3 head injury, which
might be perfectly survivable on its own, can be the injury that
kills you if you already have other major injuries. Which, as it
happens, you are very likely to have in a serious motorcycle
crash.
The COST study was limited to people who had hit their helmets
on the pavement in their accidents. Of these, 67 percent
sustained some kind of head injury. Even more㭅
percent—sustained leg injuries, and 57 percent had thorax
injuries. You can even calculate your odds using the Injury
Severity Score, or ISS. Take the AIS scores for the worst three
injuries you have. Square each of those scores—that is,
multiply them by themselves. Add the three results and compare
them with the ISS Scale of Doom below.
A score of 75 means you're dead. Sorry. Very few people with an
ISS of 70 see tomorrow either.
If you're between 15 and 44 years old, an ISS score of 40 means
you have a 50-50 chance of making it. If you're between 45 and
64 years old, ISS 29 is the 50-50 mark. And above 65 years old,
the 50-50 level is an ISS of 20. For a 45- to 64-year old guy
such as myself, an ISS over 29 means I'll probably die.
If I get two "serious," AIS 3 injuries—the
aforementioned AIS 3 head hit and AIS 3 chest thump—and a
"severe" AIS 4 leg injury, my ISS score is ... let's
see, 3 times 3 is 9. Twice that is 18. 4 times 4 is 16. 18 and
16 is 34. Ooops. Gotta go.
Drop my AIS 3 head injury to an AIS 2 and my ISS score is 29.
Now I've got a 50-50 shot.
Obviously, this means it's very important to keep the level of
head injury as low as possible. Because even if the head injury
itself is survivable on its own, sustaining a more severe
injury—even between relatively low injury levels—may not
just mean a longer hospital stay, it may be the ticket that
transfers you from your warm, cushy bed in the trauma unit to
that cold, sliding slab downstairs.
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Department Of Testing
In the other corner of the U.S. helmet cage-fighting octagon is
the DOT standard. It mandates a testing regimen of
moderate-energy impacts, which happen in 90 percent or more of
actual accidents, according to the Hurt Report and other, more
recent studies.
Where the Snell standard limits peak linear acceleration to 300
G, the DOT effectively limits peak Gs to 250. Softer impacts,
lower G tolerance. In short, a kinder, gentler standard.
The DOT standard has acquired something of a low-rent reputation
for a number of reasons. First, it comes from the Gubmint, and
the Gubmint, as we know, can't do anything right.
The DOT standard, like laws against, say, murder, also relies on
the honor system; that is, there's only a penalty involved if
you break it and sell a non-complying helmet and get caught.
Manufacturers are required to do their own testing and then
certify that their helmets meet the standards. But it also gives
helmet designers quite a bit of freedom to design a helmet the
way they think it ought to be for optimum overall protection.
The question is, how well are those designers doing their job
with all that freedom?
DOT, ECE BSI, SMF—Let's Call The Whole Thing
Off
In a typical large motorcycle dealership you're likely to find
helmets that conform to all these standards. Most U.S.-market
full-face helmets made in Asia—Arai, HJC, Icon, KBC,
ScorpionExo, Shoei, and most Fulmer models—are Snell M2000 or
M2005 certified. (The Snell standard did not change
substantially from M2000 to M2005.) Most helmets from European
companies—Vemar, Shark, Schuberth, etc.—conform to the ECE
22-05 standard.
Suomy helmets sold under its own name conform to either the ECE
or the BSI standard, but Suomy private-labels some helmets to
brands such as Ducati that are built and certified to Snell.
Some AGV models sold here are made to Snell standards, some to
BSI. And a few Asian-made helmets are DOT-only. Among major
manufacturers, Z1R (a subbrand of Parts Unlimited) and Fulmer
Helmets sell DOT-only lids at the lower end of their pricing
scales. You can also get 'em at Pep Boys under the Raider brand
name.
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Hurts So Good
To talk about helmet design and performance with any measure of
authority, we should first look at the kinds of accidents that
actually occur. The Hurt Report, issued in '81, was the first,
last and only serious study on real motorcycle accidents in the
U.S. The study was done by some very smart, very reputable
scientists and researchers at the University of Southern
California. The Hurt researchers came to some surprising and
illuminating conclusions—conclusions that have not been
seriously challenged since.
First, about half of all serious motorcycle accidents happen
when a car pulls in front of a bike in traffic. These accidents
typically happen at very low speeds, with a typical impact
velocity, after all the braking and skidding, below 25 mph. This
was first revealed in the Hurt Report but has been recently
backed up by two other studies, a similar one in Thailand and
especially the COST 327 study done in the European Union, where
people have fast bikes and like to ride very quickly on some
roads with no speed limits at all.
Actual crash speeds are slow, but the damage isn't. These are
serious, often fatal crashes. Most of these crashes happen very
close to home. Because no matter where you go, you always leave
your own neighborhood and come back to it. And making it through
traffic-filled intersections—the ones near your home—is the
most dangerous thing you do on a street motorcycle.
The next-biggest group of typical accidents happens at night,
often on a weekend, at higher speeds. They are much more likely
to involve alcohol, and often take place when a rider goes off
the road alone. These two groups of accidents account for almost
75 percent of all serious crashes. So the accident we are most
afraid of, and the one we tend to buy our helmets for—crashing
at high speeds, out sport riding—is relatively rare.
Even though many motorcycles were capable of
running the quarter-mile in 11 seconds (or less) and topping 140
mph back in '81, not one of the 900-odd accidents investigated
in the Hurt study involved a speed over 100 mph. The "one
in a thousand" speed seen in the Hurt Report was 86 mph,
meaning only one of the accidents seen in the 900-crash study
occurred at or above that speed. And the COST 327 study, done
recently in the land of the autobahn, contained very few crashes
over 120 kph, or 75 mph. The big lesson here is this: It's a
mistake to assume that going really fast causes a significant
number of accidents just because a motorcycle can go really
fast.
Another eye-opener: In spite of what one might assume, the speed
at which an accident starts does not necessarily correlate to
the impact the head—or helmet—will have to absorb in a
crash. That is, according to the Hurt Report and the similar
Thailand study, going faster when you fall off does not
typically result in your helmet taking a harder hit.
How can this be? Because the vast majority of head impacts occur
when the rider falls off his bike and simply hits his head on
the flat road surface. The biggest impact in a given crash will
typically happen on that first contact, and the energy is
proportional to the height from which the rider falls—not his
forward speed at the time. A big highside may give a rider some
extra altitude, but rarely higher than 8 feet. A high-speed
crash may involve a lot of sliding along the ground, but this is
not particularly challenging to a helmeted head because all
modern full-face helmets do an excellent job of protecting you
from abrasion.
In fact, the vast majority of crashed helmets examined in the
Hurt Report showed that they had absorbed about the same impact
you'd receive if you simply tipped over while standing, like a
bowling pin, and hit your head on the pavement. Ninety-plus
percent of the head impacts surveyed, in fact, were equal to or
less than the force involved in a 7-foot drop. And 99 percent of
the impacts were at or below the energy of a 10-foot drop.
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To Snell? Or Not To Snell?
In analyzing the accident-involved helmets, the Hurt researchers
also addressed whether helmets certified to different standards
actually performed differently in real crashes; that is, did a
Snell-certified helmet work better at protecting a person in the
real world than a plain old DOT-certified or equivalent helmet?
The answer was no. In real street conditions, the DOT or
equivalent helmets worked just as well as the Snell-certified
helmets.
In the case of fatal accidents, there was one more important
discovery in the Hurt Report: There were essentially no deaths
to helmeted riders from head injuries alone.
Some people in the study, those involved in truly awful,
bone-crushing, aorta-popping crashes, did sustain potentially
fatal head injuries even though they were wearing helmets. The
problem was that they also had, on average, three other injuries
that would have killed them if the head injury hadn't.
In other words, a crash violent enough to overwhelm any decent
helmet will usually destroy the rest of the body as well. Newman
put this into perspective. "In most cases, bottoming
[compressing a helmet's EPS completely] is not going to occur
except in really violent accidents. And in these kind of cases,
one might legitimately wonder whether there is anything you
could do."
How many people were saved because their helmet was designed to
a "higher" or "higher energy" standard than
the DOT standard? As far as the Hurt researchers could
ascertain, none.
But the Hurt Report was done nearly 25 years ago. There have
been a couple of significant accident studies done since. Both
of which, by our reading, tend to back up the Hurt Report's
findings.
And remember, these guys are investigating crashes in Europe,
where Snell-rated helmets are a rarity because they can't
generally pass the softer ECE standard required there.
In other words, the latest relevant study,
which used state-of-the-art methods and covered accidents in
countries where there are plenty of 10-second, 160-mph
superbikes running around, concluded that current
standards—even the relatively soft ECE standards—are
allowing riders' heads to be routinely subjected to forces that
can severely injure or kill them. The COST study estimated that
better, more energy-absorbent helmets could reduce motorcycle
fatalities up to 20 percent. If that estimate is legitimate and
was applied in the U.S., it would mean saving about 700 American
riders' lives a year.
There's no good reason to think things are different here in the
States than in Germany, Britain and Finland, all modern,
well-developed, superbike-rich countries. Heads are heads,
asphalt is asphalt, and falling bodies operate under the same
laws of physics there as they do here in America.
If you ask most head-impact scientists or the representatives of
the European helmet manufacturers how they like the Snell
M2000/M2005 standard, they will generally tell you it's
unrealistic, based more on supposition than on science, and
forces manufacturers to make helmets that are stiffer than they
should be.
If you ask the representatives of many of the top Snell-approved
helmet companies, they'll say the Snell standard is a wonderful
thing, and they'll imply helmets certified to lower-energy
standards—that would be any other standard in the world—are
suspicious objects, like smoked clams from the 99 Cents Only
store. And not as good at protecting you in an extremely
high-energy mega-crash as a Snell-approved helmet is.
What the Snell advocates won't tell you is that when these same
makers sell their helmets in Europe, Japan and the U.K., they
are not the same helmets they sell here, and they're not Snell
rated. They are built softer, tailored to conform to exactly the
same ECE or BSI standards as the European makers.
If you get these two groups of folks in a room together and ask
these questions, we'd suggest wearing a helmet yourself.
Can Less Be More?
In the last 10 to 15 years a number of Asian-made helmet brands
such as HJC, Icon, KBC and Scorpion have entered the market to
challenge the once-reigning Japanese leaders, Shoei and Arai.
These new brands offer helmets that look and feel pretty much
like the Arais and Shoeis we were used to wearing and seeing on
all the magazine covers, but at substantially lower prices. Problem
is, a lower price, especially in a potentially li/fe-saving
piece of safety equipment, can do as much harm as good to a
brand. There's always the perception lingering in a buyer's
mind that a product can't be as good or protect as well if it
doesn't cost as much.
So what can a lower-priced maker do to enhance its brand
reputation? Get Snell certified. Whether they think a
Snell helmet is actually better at head protection or not—and
there's no shortage of debate on that subject—they're
essentially over a barrel. If they don't get Snell certified,
they give the perception their products are not as good as the
others on the shelf. And their helmets will sell like Girls Gone
Wild videos at a Village People concert.
In six months of researching this article, I spoke to many
helmet company representatives. Some in civil tones. Some not so
much. One, in particular, summed up the Snell-or-not quandary
best. It was Phil Davy, brand manager for the very popular Icon
helmets and riding gear. "When you build a helmet for this
market, meeting the Snell standard is your first, second, third,
fourth and fifth concern. You can then start designing a helmet
that's safe," he said.
It is important to note that every one of Davy's Icon helmets is
Snell certified. He's no fool.
AVERAGE Gs
Fewer Gs = Less chance of brain injury
DOT-only helmets:
Z1R ZRP-1 (P)
Average: 152 Gs
LF: 148 gs
RF: 176 gs
LR: 153 gs
RR: 130 gs
Fulmer AFD4 (P)
Average: 157 Gs
LF: 152 gs
RF: 173 gs
LR: 175 gs
RR: 130 gs
Pep Boys Raider (P)
Average: 174 Gs
LF: 163 gs
RF: 199 gs
LR: 185 gs
RR: 152 gs
BSI/DOT Helmets
AGV Ti-Tech (F)
Average: 169 Gs
LF: 156 gs
RF: 199 gs
LR: 195 gs
RR: 129 gs
Suomy Spec 1R (BSI) (F)
Average: 182 Gs
LF: 192 gs
RF: 215 gs
LR: 197 gs
RR: 126 gs
ECE 22-05/DOT Helmets
Schuberth S-1 (F)
Average: 161 Gs
LF: 151 gs
RF: 180 gs
LR: 176 gs
RR: 137 gs
Suomy Spec 1R (ECE) (F)
Average: 171 Gs
LF: 156 gs
RF: 200 gs
LR: 190 gs
RR: 140 gs
Shark RSX (F)
Average: 173 Gs
LF: 166 gs
RF: 187 gs
LR: 201 gs
RR: 141 gs
Vemar VSR
Average: 174 Gs
LF: 171 gs
RF: 198 gs
LR: 166 gs
RR: 162 gs
Snell 2000/DOT Helmets
Icon Mainframe (P)
Average: 181 Gs
LF: 168 gs
RF: 217 gs
LR: 189 gs
RR: 152 gs
Icon Alliance (F)
Average: 183 Gs
LF: 179 gs
RF: 200 gs
LR: 179 gs
RR: 175 gs
Scorpion EXO-400 (P)
Average: 187 Gs
LF: 185 gs
RF: 212 gs
LR: 193 gs
RR: 158 gs
AGV X-R2 (F)
Average: 188 Gs
LF: 192 gs
RF: 226 gs
LR: 166 gs
RR: 167 gs
Arai Tracker GT (F)
Average: 201 Gs
LF: 193 gs
RF: 243 gs
LR: 203 gs
RR: 166 gs
HJC AC-11 (F)
Average: 204 Gs
LF: 195 gs
RF: 230 gs
LR: 231 gs
RR: 163 gs
Scorpion EXO-700 (F)
Average: 211 Gs
LF: 207 gs
RF: 236 gs
LR: 226 gs
RR: 176 gs
Impact Key: LF: Left Front, 7-foot drop, Flat
Pavement. RF: Right Front, 10-foot drop, Flat
Pavement. LR: Left Rear, 7-foot drop, Flat Pavement.
RR: Right Rear, 7-foot drop, Edge Anvil. Shell Key:
(P): Polycarbonate (F): Fiberglass
|
The Rules Rule
OK. We promised an actual helmet impact test, and it's time to
give it to you.
We asked the major helmet brands sold in the U.S. to each pick
one model of their helmets. We asked for two functionally
identical helmets in the same size, medium or 71¼4. Why two? To
give us a look at the consistency of the manufacturer's
production techniques. Why all one size? To make sure any
differences we saw were due to design and production
differences, not random differences due to sizing. And we wanted
to use the same-size headform in all our testing, again for
consistency. We were also interested in learning as much as we
could about different helmet constructions, and about how
helmets built to different standards vary. So if a manufacturer
made both fiberglass-shell and plastic-shell helmets, we asked
for a pair of each. And if a manufacturer made helmets to two
different standards, we asked for both as well.
Icon and Scorpion sent both fiberglass and polycarbonate
helmets, all Snell/DOT-rated. AGV sent a pair of Snell/DOT-rated
X-R2s and a pair of BSI/DOT-rated TiTechs. And Suomy sent the
same model, its Spec 1R, in both BSI-rated and ECE-rated
versions.
In the end, we wound up with 16 models, 32 helmets in all. A
look at the accompanying chart will give you a rundown of the
helmet brands that elected to participate and the models they
sent. A number of manufacturers chose not to participate: Bell,
KBC, OGK, Shoei and Simpson were contacted repeatedly, but chose
not to send helmets. We also tested a couple of full-face Raider
helmets purchased from Pep Boys for $69.95 a pop.
Unlike other standards testing, where the test parameters are
published years ahead of time, we did not reveal the actual
tests we were going to perform before we did the testing. So
there was, essentially, no chance for them to send mislabeled,
ringer helmets.
We needed somebody to help us design the tests and do the actual
testing. So we hired David Thom. Remember the Hurt Report? Thom
was one of the USC researchers who went out to investigate all
those motorcycle accidents and then helped pull it all together.
Thom worked at USC with Professor Harry Hurt for many years,
investigating all the various ways motorcyclists and other folk
hurt themselves, and striving mightily to find better ways to
protect them.
Thom subsequently formed his own company, Collision and Injury
Dynamics. He has his own state-of-the-art helmet impact lab
where he does impartial, objective certification testing for
many helmet companies. The DOT standard, for instance, relies on
companies certifying their own helmets, and Thom is one of the
people they contract with to do the actual testing. In other
words, he knows what he's doing.
We had no interest in checking to see whether our helmets
conform to any specific standard. Because a helmet's job is
protecting your head, not passing a standard. We came up with
our own battery of tests designed to duplicate, as best we
could, the impacts that really happen on a statistically
significant basis.
Real motorcycle accidents don't end with a helmet hitting a
machined stainless-steel anvil—they end up with a helmet
bashing down on good old lumpy, gravel-studded asphalt. So the
industrious Thom grabbed a square-foot piece of Sheldon Street
in El Segundo, California, the street out in front of his lab,
when the paving crew tore it up for resurfacing. Set in
concrete, that would be our "anvil," as they say in
the biz, for flat-surface impacts.
Three of the four impacts we planned for each helmet would be on
that flat asphalt surface—simply because that's what real
motorcyclists land on when they fall, more than 75 percent of
the time. The Hurt Report established this, and in the recent
Thailand helmet study 87.4 percent of the helmet hits were from
the road surface or the shoulder. Helmets do hit curbs a small
percentage of the time, but usually after sliding along on the
road first, which means that in most cases they are actually
hitting a flat surface—the vertical plane of the curb.
For the energy of each drop, we selected a range of hits typical
of both the DOT and Snell testing regimens. We hit the left
front and the left rear of the helmets with an energy of 100
joules, which translates to a drop of about 2 meters, or 6.6
feet. According to the Hurt Report, this drop represents the
90th-percentile energy of the crashes they investigated. We also
did one high-energy drop with an energy of 150 joules, the same
energy—about a 10-foot drop—as the hardest hit specified in
the Snell standards, on the right front of each helmet. That's
66 percent more violent than the drop specified by the DOT
standard for a medium-sized helmet, and represents the
99th-percentile impact seen in the Hurt Report. Which means 1
percent or fewer impacts seen on the street exceeded this energy
level. So we weren't exactly taking it easy.
To see what happens when you're unlucky enough
to rear-end a truck's lift gate, slide into a storm drain or be
flung into the Eiffel Tower, we also did an edge hit onto a
scary-looking piece of upright steel bar. We debated whether to
do this hit at a 2-meter, 100-joule energy level or a more
violent 3-meter, 150-joule impact level. We opted for the
smaller hit, more to protect the helmet test rig than to play
nice with the helmets. If a single helmet bottoms out and
squishes its EPS liner flat, the total impact goes right into
the headform and test rig—as it would to your head. And just
like your head, the test rig is gonna break. We weren't sure all
the helmets would survive the 150-joule edge drop, so we pulled
back to the 100-joule level. Fracturing the rig would put us out
of commission for days, and we didn't have the time—or
money—to risk that.
In the end we were too conservative. When we inspected the
helmets after the full course of testing, the 100-joule edge hit
hadn't come close to bottoming any of the helmets—even the
supposedly wimpy DOT-only ones. We are confident we could have
done the edge test at the 99th-percentile 150 joules—the Snell
edge-anvil test—and seen results commensurate with those we
saw from the other impacts.
The results of all our laborious impact testing were exactly as
expected—but still surprising as hell.
The helmets ranged from the softest regimen, the DOT standard,
to the Snell standard, the stiffest. But would the real-world,
production-spec helmets actually show that progression from soft
to stiff? In other words, can you predict how stiff a helmet
will be simply by looking at the standard label? Absolutely.
In fact, our results show that modern helmets are all made with
an amazing degree of precision, with their shell construction,
liner density and liner thickness all controlled very well in
the production process. In other words, almost everybody
designing serious helmets seems to know exactly how to get what
they want—the only variable is deciding what they want. And
for the most part, the standards make that decision for them,
not flashes of genius on the parts of the helmet designers
themselves.
All the helmets we tested performed exactly as the standards
they were designed to meet predicted. And they seemed to exceed
those standards—that is, the DOT-only helmets were better at
high-energy impacts than they had to be just to pass the DOT
standard, and the Snell helmets were better at absorbing
low-energy impacts than they had to be to pass DOT or Snell. So
choosing a helmet, at least in terms of safety, is not a
question of choosing high or low quality, it's one of choosing
what degree of stiffness you prefer, finding a helmet in that
range by choosing a particular standard, and then worrying about
fine points like fit, comfort, ventilation, graphics, racer
endorsements or computer-generated spokesmodels.
|
How Hard Is Hard?
Not one helmet came close to bottoming in any of our tests. And
they all handled the low-energy impacts, even the scary-looking
edge impact, without strain.
In fact, in most cases the peak Gs in the edge impact were lower
than the flat-anvil peak Gs for the same helmet at the same
impact energy. Why is this? Because the edge impact flexes
and/or delaminates the helmet shell sooner in the impact,
letting the EPS inside—the real energy absorber in the
system—start doing its work sooner.
In the high-energy impact, the 3-meter, 150-joule drop—the
kind of hit a Snell helmet is, presumably, designed to
withstand—the differences became more apparent.
The stiffest helmets in the Big Drop test, the Arai Tracker GTs,
hit our hypothetical head with an average of 243 peak Gs. The
softest helmets, the Z1R ZRP-1s, bonked the noggin with an
average of 176 peak Gs. This is a classic comparison of a stiff,
fiberglass, Snell-rated helmet, the Arai, against a softer,
polycarbonate-shell, DOT-only helmet, the Z1R. OK. So let's
agree that we want to subject our heads to the minimum possible
G force. Should we pick an impressive, expensive
fiberglass/Kevlar/unobtanium-fiber helmet—or one of those
less-expensive plastic-shelled helmets?
Conventional helmet-biz wisdom says fiberglass construction is
somehow better at absorbing energy than plastic—something
about the energy of the crash being used up in delaminating the
shell. And that a stiffer shell lets a designer use softer foam
inside—which might absorb energy better.
Our results showed the exact opposite—that plastic-shelled
helmets actually performed better than fiberglass. In our big
3-meter hit—the high-energy kind of bash one might expect
would show the supposed weaknesses of a plastic shell—the
plastic helmets transferred an average of 20 fewer Gs compared
with their fiberglass brothers, which were presumably designed
by the same engineers to meet the same standards, and built in
the same factories by the same people.
Why is this? We're guessing—but it's a really good guess: The
EPS liner inside the shell is better at absorbing energy than
the shell. The polycarbonate shells flex rather than crush and
delaminate, and this flexing, far from being a problem, actually
lets the EPS do more of its job of energy absorption while
transferring less energy to the head.
Remember, these polycarbonate helmets from both Icon and
Scorpion are also Snell M2000 rated. So they are tested to some
very extreme energy levels. And Ed Becker, executive director of
the Snell Foundation, is on record as saying that a
low-priced—that is, plastic-shelled—Snell-certified helmet
is just as good at protecting your head as a high-priced—that
is, fiberglass—Snell-certified helmet. So at the high end of
impact energy, we have the Snell Foundation vouching for their
performance. And our testing, without the extreme two-hit hemi
test, says they're actually superior.
Score One For Faceless Government Bureaucrats
The DOT helmets we had were all plastic-shelled, and none cost
more than $100. How did they do? They kicked butt. In what must
be considered a head-impact Cinderella story, the DOT-only
helmets from Z1R delivered less average G force to the headform
through all the impacts than any others in the test.
And they still excelled in the big-hit, 150-joule impact—a
blast 66 percent harder than any actual DOT test for a
medium-sized helmet.
The Z1R ZRP-1s continuously amazed us. After all the testing,
its outer shell looked essentially unharmed: The slight road
rash at the impact sites caused by our stubborn insistence on
hitting actual pavement looked no worse than we'd expect if the
helmet had fallen off the seat at a rest stop.
When we pulled the ZRP-1s apart, the EPS had cracked and
compressed at the impact sites, just as it's supposed to do, and
just as it did in every other helmet. But it had come nowhere
near bottoming; there was still an inch or more of
impact-absorbing foam left. And the plastic shell seemed
completely unharmed, from the inside as well as the outside,
even where it had taken the terrifying edge hit and the big
three-meter bash.
This illustrates just how hard it is to tell from the outside
whether a helmet has taken a severe hit. And why you should
never, ever buy a used helmet.
Fiberglass helmets such as the the Arai
Tracker (shown) showed substantial damage to their
shells after the edge impact. The polycarbonate-shell
helmets were largely unmarked. Neither result is
essentially better: Either shell material can be used
to make excellent helmets. Polycarbonate helmets
generally transmit fewer Gs to the head in our testing
than fiberglass-shell lids, even when certified to the
same standards.
|
The Hardest Hits
So the softest DOT helmets came through our tests with
protection to spare. But doubt lingered, in spite of everything
we had seen: How would they do in a monster, wicked-big impact?
So we decided to kill them. We ran the Z1Rs up the test rig one
last time. Not just to the 10-foot, 150-joule Snell test height,
but all the way to the top of the rig: 3.9 meters, or 13 feet.
This hit would be at 8.5 meters per second, an energy of 185
joules. That's higher and harder than any existing helmet
standard impact. And, not coincidentally, the same height and
energy called out in the COST 327 proposed standard, the one
that may replace the current ECE 22-05 specification. We did one
hit on the pavement and one on the curb anvil—the same hits
called out in the COST proposal. We did them on the back of the
helmets, in the center, because that was the only place we
hadn't hit them before.
So this last test is not directly comparable to the others. But
it showed, in no uncertain terms, just how tough—and how
protective—an inexpensive helmet can be.
The peak Gs for the monster hits were 208 for the curb impact
and 209 for the flat-pavement impact. Just a few Gs more, that
is, than many of the Snell-rated helmets transmitted in their
seven-foot hits on the flat anvil. And even after these mega
hits, the EPS liners were still nowhere near used up.
The ZRP-1s are also well finished, quiet and
very comfortable, though maybe a little short on venting.
They're also light: Our ZRP-1s weighed only about an ounce more
than the lightest helmets in the test, the Arai Tracker GTs.
What's the cost for all this excellent impact absorption,
comfort, light weight and highly durable finish? In a solid
color, a ZRP-1 retails for $79.95.
The least-expensive helmets in the test, the $69.95 Pep Boys
Raiders, also did well in all the standard impacts. But we can't
recommend them because their chin bars have soft, resilient
foam, not the EPS you need to absorb a severe head-on impact.
Our advice is to spring for the extra $10 and treat yourself to
a Z1R ZRP-1.
Another helmet that taught us a thing or two was the Schuberth
S-1. The Schuberth is certified to the ECE 22-05 standard, which
dictates impact energies marginally higher than the DOT
standard. Like the Z1R ZRP-1 and the Fulmer AFD4, it has
relatively large outer dimensions, leaving room in the shell for
thicker, and presumably softer, EPS. And like the DOT-only lids,
it soaked up energy like a sailor soaks up Schlitz. If you can't
bring yourself to wear a $79.95 helmet just to get excellent
energy management, you'll feel very comfortable with the
Schuberth, which sells for $640 to $700.
The other helmets we pulled apart used either a one-piece or a
two-piece EPS liner. The S-1, on the other hand, uses a complex,
five-piece liner, with separate front, rear and overear pads
glued to a central foam hat. Leave it to the Germans to use five
parts to do what the Z1R does with one.
A few of the European helmets—the Vemars, the Sharks and the
Suomys—use a different kind of EPS liner than we're used to
seeing in Asian-built helmets. Instead of a solid foam liner of
a specific density, these Euro-lids use stiffer, more rigid foam
with deep channels in it to soften up the assembly and vent air
through the shell. The effect is that of a highly vented bicycle
helmet stuffed into the requisite hard outer shell. The ECE-rated
Vemars and Sharks and the ECE and BSI-rated Suomys performed
well on the impact torture rack, showing generally lower
G-transmission than we saw in typical Snell-rated helmets.
|
The Human Race
"But I'm a racer," we hear you rationalizing. "I
go really fast. I go so fast, in fact, that I need a very
special, high-energy helmet to protect my wonderful manliness
and fastness." Not so, Rossi-breath.
If you're going to land on flat pavement when you crash—and
you almost always do—you can afford to wear a softer ECE or
DOT helmet, because softer helmets do a very good job of
absorbing big impacts—even really, really big impacts—on
flat surfaces. Remember, the hard part about getting a helmet
past the Snell standard involves surviving that mythical steel
orange very hard twice in the same spot on the helmet,
simulating a monster hit—or two—on, say, a car bumper. Been
to Laguna Seca recently? No car bumpers or steel oranges
anywhere.
Racers don't typically hit truck parts, storm drains, sign
posts, tree shredders or the Watts Towers. They fall off,
sometimes tumble, and almost always hit the racetrack. Or maybe
an air fence, a sand trap or hay bale. In other words, the
racetrack is the best-controlled, best-engineered, softest,
flattest environment you're going to find. Racers are even more
likely to hit flat pavement than street riders—and street
riders hit flat pavement around 90 percent of the time.
The AMA accepts DOT, ECE 22-05, BSI 6658 Type A or Snell
M2000-rated helmets. That's for going 200 mph on a superbike at
Daytona. The FIM, which sanctions MotoGP races all over the
world, accepts any of the above standards but DOT. Why not DOT
if DOT helmets are comparable to ECE helmets? Because the DOT is
an American institution, and the FIM doesn't really do American.
And because the DOT standard doesn't require any outside
testing—just the manufacturers' word that their helmets pass.
Yes, Size Does Matter
There's one more issue with the Snell and BSI standards we
should mention, even if we didn't specifically address it in our
testing.
Snell and BSI dictate that every helmet be impact-tested with
the same-weight headform inside, no matter the size of the
helmet. That is, an XS helmet is required to withstand exactly
the same total impact energy as an XXL.
The DOT and ECE standards vary the energy of the impacts by
varying the weight of the headform, under the reasonable
rationale that a very small head weighs less than a very big
one. In the eyes of the governments of both the U.S. and the
European community, in other words, helmet makers should tailor
the stiffness of their helmets to suit the head sizes of the
wearers to protect everybody's brain equally.
What does this mean to you? If you have a relatively heavy head,
the difference in stiffness between a Snell helmet and a DOT or
ECE helmet will be relatively small. If you are a man, woman or
child with a lighter head, on the other hand, the difference in
stiffness between a Snell helmet and a DOT or ECE helmet will be
relatively huge.
So if you are concerned after reading all this that a Snell
helmet might be too stiff for you, Mr. XXL, you should be even
more concerned about putting your XS wife or child into a Snell
or BSI helmet. The Snell Foundation's position on this is that
they have no proof big heads weigh more than small heads. Hmmm.
Isn't a head basically a shell of thin bone filled with water?
Doesn't more bone and water weigh more than less bone and water?
And it's not just us. One study by Mr. Thom concluded that head
weight does increase with head circumference. He found there is
good evidence that smaller heads weigh less and that smaller
helmets should thus be softer.
As Thom says regarding the Snell Foundation's position on this:
"They are not in touch with reality." |