Fordnatics List Archive

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Mail From: "On a Pentium life is like a box of chocolates..." <(email redacted)>

Can anyone tell me the required snell rating for an NHRA helmet?
I'd like to drag race my Stang at Sears Point (if the rain ever
stops) and I have to buy a helmet.

Thanks,

Roger Hupfauer
'91 GT
7.96@151 juuuuust kiddin'

email: (email redacted)
(I don't subscribe to this list)

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Mail From: Kelly Murray <(email redacted)>


A Snell 80 is good until 1996. A Snell 85 is good till 2001.

I would buy a Snell 90 if paying anything significant for one.
A new one should be a Snell 95.

-Kelly Murray

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Mail From: (email redacted) (Benjamin Levy)

To: <(email redacted)>
Cc: (email redacted)
Subject: Re: Snell rating for NHRA approved helmet
From: Kelly Murray <(email redacted)>

A Snell 80 is good until 1996. A Snell 85 is good till 2001.

I would buy a Snell 90 if paying anything significant for one.
A new one should be a Snell 95.

It couldn't hurt (other than your wallet to look for a Snell xxSA
(special application). A standard motor cycle shop will usually just
carry Snell xxM (motor cycle) helmets. I'm not sure what the
difference is, but there are some tracks require Snell 90SA.
---Ben Levy <(email redacted)>

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Mail From: (email redacted) (Scott Griffith, Sun Microsystems Lumpyware)

On Mar 22, Kelly Murray wrote:

> A Snell 80 is good until 1996. A Snell 85 is good till 2001.
>
> I would buy a Snell 90 if paying anything significant for one.
> A new one should be a Snell 95.

The Snell 95 specs have not yet been adopted ( I have a copy of the
draft spec, though). They should be adopted by the end of the year,
and Snell 95 helmets should be available by early next year some time.
I got all the relavent information while researching changes in the
rules package that my club has adopted this year, and I'm in the
process of writing up an article on it for our newsletter.

Definitely, if you're going to get a helmet for motorsport use, get an
SA90 helmet. The M90 helmets are also very good, and are accepted by
*some* sanctioning bodies, but the SA helmet will give you the most
flexibility. You can find SA85 helmets for _cheap_, but that's becuase
they've been sitting on the shelf aging for at least 3-4 years. Give
the bargains like that a miss.

Even though the tech guys from your sanctioning body may accept older
helmets, keep a close eye on them, and think seriously about replacing
them after 5-7 years. The various materials, most importantly the
closed-cell foam shock absorber layer, lose some of their properties
with age. An older helmet wil transmit a higher acceleration to the
wearer's head in a crash as the foam ages. The Snell Foundation, the
Motorcycle Safety Institute, and the SFI all agree that 5 years is
about the maximum period that you ought to use a helmet for before
replacement.

I can already hear some of you warming up the flamethrowers on this
one, with the claim that "they only say that to sell more helmets".
It's true that the SFI is a manufacturer-supported group, and that
concern might well apply there. But the Snell Foundation and the MSF
are both non-profit testing agencies, so they're not just trying to
"sell helmets". One of the reasons I researched this was that I wanted
to convince myself that these aging rules were not just an
industrywide technique used to guarantee repeat customers. After
interviewing the chief of the Snell Foundation's testing lab, I'm now
convinced that they aren't.

Here's an example of helmet aging. How many folks here have actually
checked their chinstrap attachments? Not the buckle or the visible
webbing, but the actual attachment. Many vendors use a single
mild-steel tubular rivet and backing washer for attachment of the
webbing to the shell. The chlorides from your perspiration can attack
the rivet and the resulting pitting can cut its ultimate strength by s
sizable fraction.

If you're running a 4- or 5-season old helmet, and you see a lot of
seat time (especially in a warm climate), you might do yourself a
favor to just look over this hidden, often ignored hardware. I
suspect that there'll be a few folks out there who may accelerate
their own helmet replacement schedule after doing this for the first
time. It doesn't take much salty perspiration, or very much elapsed
time, to really go after that hardware. If it's corroded halfway
through, the chinstrap's retention force is reduced by half. And a
helmet only protects to spec when it stays on...

Play safe!

-skod

- --
Scott Griffith, Sun Microsystems Lumpyware
Nor Cal SAAC/Green Flag Driving Association driving instructor
(and driver, of anything that turns both right and left,
and can pass tech...) Return Path : (email redacted)

This read-only message was archived from a public mail list.
Mail From: (email redacted) (Scott Griffith, Sun Microsystems Lumpyware)

On Mar 23, Benjamin Levy wrote:

> It couldn't hurt (other than your wallet to look for a Snell xxSA
> (special application). A standard motor cycle shop will usually just
> carry Snell xxM (motor cycle) helmets. I'm not sure what the
> difference is, but there are some tracks require Snell 90SA.

Well, there are several differences. Most importantly, the SA helmet
spec is subjected to one more impact during the series of impacts used
to rate the helmet, and the object that is used for this additional
impact is shaped like a section of roll bar tubing (as opposed to the
various round, flat, and pointy forms used in the M rating). The spec
says that the helmet has to withstand the entire series of impacts
without failing, without subjecting the headform inside to more than a
specific level of acceleration, and so on. I won't include it here,
since the spec is about 60 pages...

The liner of an SA helmet also must be made of fire retardant
materials (Nomex, PBI/Kevlar, and so on). The M spec helmets do not
need to be. The dimensions of the eyeport are also slightly smaller
for an SA helmet. An M-rated helmet has to allow the DOT-specified
motorcycle helmet field of view (for traffic safety reasons). The SA
helmet has a *slightly* smaller field of view (in general, in the
vertical plane, for glare-reduction reasons). But in return it
supports its faceplate more efficiently, allowing it to withstand
heavier impacts with debris and so on and still protect the driver's
eyes.

The faceplate requirements for both M and SA helmets were updated as
of the Snell 90 specs to require the same impact resistance.
Essentially, a .22 caliber lead pellet (1 gram) is propelled via an
air gun at some specified velocity (250mph comes to mind- my materials
are at home). It is allowed to impact anywhere on the faceplate, and
cannot penetrate, or kick loose any debris or shrapnel inside the
helmet in the vicinity of the eyes. That's a tough spec! That's why
all new Snell helmets come with .125" polycarbonate faceplates,
instead of the thin .064" allowed under the old M85 spec.

Some of the SA90 helmet manufacturers also included a fire-retardant
chinstrap cover, but later versions have substituted more fire
retardant webbing instead. Makes fastening the chinstrap easier. Also,
many manufacturers also put much more padding in the cheekbone and
basal skull areas on the SA helmets, both to provide better facial
protection in an impact, and to stabilize the helmet on the wearer's
head in aerodynamic buffeting situations.

That's basically it, in a nutshell. SA helmets are *much* better if
you face the risk of direct exposure to fire, for example if you have
the fuel or oil tanks in the cockpit with you (instead of separated
out by bulkheads). To drive a Formula car, sports racer, or other car
where you're sitting in a recess in the fuel cell, these are a
must-have, period. To run a late Mustang at a local dragstrip on
Saturday night, *maybe* the fire retardance is overkill.

But then again maybe not. You just never know when you're gonna walk
out of the house to go to work some morning and find an Indycar in the
driveway with the motor running, or decide to go to a pro driving
school and try on a Formula Ford. Might as well be prepared, no? Good
SA90 helmets are about $250 and up, and are a good 5-year investment.

As many people have said: only buy a cheap helmet if you have a cheap
_head_.

-skod

- --
Scott Griffith, Sun Microsystems Lumpyware
Nor Cal SAAC/Green Flag Driving Association driving instructor
(and driver, of anything that turns both right and left,
and can pass tech...) Return Path : (email redacted)