William "Pete" Snell was an amateur auto racer. He died needlessly in a racing event in 1956 when his then state-of- the-art helmet failed utterly to protect him. His friends, including Dr. George Snively, formed the Snell Memorial Foundation to remember Pete Snell and to encourage the development and use of truly protective helmets.

The current requirement at most BMW driving schools and all club races is the use of either an open face or full face Snell SA 90 or later helmet. Currently, you cannot buy anything more current than an SA 95 helmet but the new SA2000 standards have been announced and manufacturers will be going into production shortly. For more information about the Snell Foundation and to read about their latest standards go to their web site at: http://www.smf.org/.

The article which appears below was written by Richard Welty of Krusty Motorsports in 1997. It's a bit dated since it doesn't take account of the latest test standards but its still my favorite piece on the subject. It is reproduced here with the kind permission of the author. It is followed by some detailed fitment recommendations courtesy of Bell Helmets. Their web site is: http://www.bellhelmets.com/.

Finally, you may want to consider getting a fire retardant neck collar to wear along with your helmet. The weight of your helmet contributes to fatigue in your neck muscles as you maneuver your car around the corners and a collar provides additional support. More importantly, a neck collar helps hold your head erect in the event of a crash reducing the risk of injury. On the downside, racers do report feeling confined wearing them. I carry mine with me all the time but I'm foolish and don't always wear it especially when the weather is warm.

It seems to me that I've written this article a couple of times in my life. It's time for another iteration on selecting helmets for Autocross, Driving Schools, and Racing. This one has more detail on the actual testing procedures than years past; it's all the boring stuff right at the start.

All Those Standards

There are four different tests for helmets in use in the US, and since 1985, there has been a distinction between Motorcycle and Racing (SA) helmets. We're going to start by actually outlining the tests that are used, since this seems to be an ongoing topic of very confused discussion all over the Internet. After that we'll look at other issues affecting helmets, including how to buy one in a proper and sensible manner.

DOT FMVSS 218

The US Government is responsible for one of the oldest of the Standards, DOT FMVSS Number 218. This is a motorcycle helmet standard. It is not of any direct interest for any modern motorsports activity, but establishes a number of definitions and procedures that are used in other more directly relevant standards. Among its specifications are two types of steel test anvils (one hemispherical and one flat) and the general style of testing. DOT FMVSS 218 requires two impacts of a helmet on a flat anvil when dropped from 183cm and two impacts of a helmet on a hemispherical anvil when dropped from 138cm; for the helmet to pass, the headform inside the helmet must not be subjected to more than 400G. In addition, a 3kg steel striker is to be dropped on the helmet from 300cm, and must not contact the headform which is "wearing" the helmet at the time of the test. Finally, there is a chin strap retention test which preloads the chin strap with 23kg, and then adds a test load of 136kg. The chin strap must not extend more than 25.4mm (one inch).

ANSI Z90.1-1992

A more directly useful standard is ANSI Z90.1-1992; this is a update of the original ANSI Z90.1 standard of 1966. ANSI Z90.1-1992 is accepted by many organizations as an Autocross helmet, and is appropriate for SCCA Solo II competition. ANSI Z90.1 depends on many of the definitions of DOT FMVSS 218; it specifies pre conditioning of the helmets with low (-10 degrees C) and high temperatures (50 degrees C) before testing as well as testing at ambient temperature. A water immersion pre conditioning is also specified (between 4 and 24 hours in water at between 18 degrees and 27 degrees C before testing.) The standard specifies the velocity of the impact rather than the height from which the helmets are to be dropped, but the flat and hemispherical anvils from DOT FMVSS 218 are to be used, and the headform acceleration standard is tighter, with the limit at 300Gs. The ANSI Z90.1 standard also adds an "edge" anvil to the hemispherical and flat anvils. The chin strap retention test has the same 23kg preload, with a dynamic test load consisting of a 38kg mass dropped 120mm to provide an abrupt load on the strap. The Z90.1 standard does not appear to include the dropping of a striker on the test helmet. It does, however, include a solvent test which involves wiping the helmet with a 50/50 mixture of Toluene and Benzene. The actual purpose of the solvent test is unclear to me.

Snell M and SA standards

The Snell standards are the ones most widely accepted for Racing and Driving School applications, and recent Snell standards are acceptable for SCCA Solo II competition as well. The Snell Foundation updates their standards for Motorcycle and Special Application (Road Racing) usage every 5 years; for example, 1995 Snell standard conforming helmets started to appear in early 1996. Before 1985, the Snell Foundation only had one standard for vehicular helmets, but in 1995, the Motorcycle and SA categories were separated from each other. A helmet's conformance with Snell standards is indicated by the presence of a Snell sticker inside the helmet liner (some helmets have a cloth Snell "sticker" sewn to the chin strap, but this is rare.) The Snell sticker is brightly colored and the year and level of protection is in white against the colored backdrop. Currently, SCCA Solo II permits any Snell 85 or newer helmet (M or SA), but SCCA Road Racing now requires Snell SA90 or SA95. Other organizations will vary, but many take their cue from the SCCA.

The Snell Foundation requirements are similar to the ANSI Z.90, but there are some additional requirements; for example, the ANSI standard doesn't cover painting helmets, but the Snell Foundation requires that they be paintable without compromising the protection. Furthermore, the Snell Foundation requires SA helmets to have Nomex liners instead of the more common and cheaper Nylon (if you didn't know, Nylon does really, really, really bad things to skin in a fire.) The Snell Foundation has the 3kg steel striker test, and a chin bar test for helmets with chin bars, consisting of dropping a 5kg weight onto a helmet from a height of 0.62 meters.

Many claim that there are differences between Motorcycle and SA helmets based on the difference between a "hit and slide" motorcycle accident and a "bounce around inside the vehicle" accident. There is nothing that I can see in the standards themselves to support this claim, although a manufacturer certainly might implement motorcycle helmets differently from SA helmets. It is almost certain that helmets from the top manufacturers would pass both standards except for small details like the Nomex liner requirement.

SFI 31.2

SFI has been in the automotive & racing standards business for a long time; their standards for suits, window nets, "ballistic blankets" for flywheels in drag cars, etc., have been the accepted norm in racing for some time now. They are a new player in the helmet standard game, and at the present time, are not a guiding force. They may be at some time in the future, and are certainly no slouches at safety standards.

Helmet Standard selection

I described the standards above. Now, let's talk about how to select a helmet. First of all, if you're going road racing, get the latest Snell SA model; this is a no brainer. If you're doing Marque club schools, you might as well get the latest Snell SA model, as you may decide you want to go road racing and if that happens, you're going to need one anyway.

For autocrossing, it's less obvious. If autocrossing is all you're ever going to do, then you are unlikely to need an SA helmet, as serious autocross fires are virtually non-existent. But if you think you might go road racing some day, then seriously consider SA helmets. The additional cost to get from Snell M to Snell SA is typically about $30.

Helmet Age

The SCCA has generally tended to want to make older helmets go away, especially in Road Racing (this year they tightened up the Solo II standards for the first time in a while.) Since there hasn't been a lot of change in the Snell standards since 1985, one might wonder why. The reason is that helmets do age, particularly the foam liners. I have seen the liners in old Snell 75 helmets coming out in pieces. The liner (which is the primarily protective piece) is worthless long before it actually starts breaking up. Helmets should be retired after they've served for 5 or so years of serious usage, because you simply don't know how well they're going to work after they're that old.

Helmet Fit

Helmets need to be reasonably tight, or they won't do their job properly. When you put on a helmet, you need to wiggle it about to see if the skin on your forehead moves a little; if it doesn't, the helmet isn't tight enough. But don't get a helmet that's too tight; it'll give you a headache and ruin your concentration. If you are going to wear a balaclava with the helmet (the SCCA requires them for road racing drivers with facial hair) then use one when trying on helmets. Sizes vary between manufacturers; Bells run smaller than Simpsons, in my experience. Fit is an important enough issue that you probably want to avoid mail order until you've found out what your size is for a particular manufacturer. You may find that helmets from one manufacturer fit you better than another, and good fit is the primary concern, so don't buy a poor fitting helmet just because you like one name brand better than another.

Full Face or Open Face

This depends on a lot of things. Drivers in open cars lean towards Full face helmets, although the SCCA still permits goggles with Open Face helmets. Drivers in closed cars are starting to lean towards full face helmets, as large objects have been known to penetrate windshields. I personally wouldn't use anything other than a full face helmet, and I drive a Sedan in ITB. If you do buy a Full Face helmet and you wear glasses, then make sure that the eyeport is large enough. It can be very difficult to put on glasses with some of the expensive Full Face helmets. Full Face helmets tend to have fog problems. The remedy for fogging that has worked for me has been to have an Extremely Clean visor with Fog City anti fogging agent liberally applied to the inside. That, and some Rain X on the outside to help with rain in an open car can make visibility a lot nicer; if you try and drive an open wheel car in the rain with your visor cracked open, you'll get a face full of water for your trouble the first time your turn a corner.

Don't Throw It

First time you bounce your helmet off the pavement when you're mad about your session, you've just written it off. Throw your driving gloves; they're harder to break. A good thing to keep in mind is that helmets, like seat belts, are use once devices. Once they're overstressed, it's time to retire them.

Kevlar vs. Fiberglass

The Kevlar ones are more expensive, and lighter. It's a matter of taste and wallet heft.

Store And Transport It Sensibly

A helmet bag is a good idea, especially a padded one. Helmets are expensive; don't abuse them unnecessarily.

Hope this helped...

That's a dump of the stuff that I know about helmets. Keep in mind that any of the major helmet companies makes a respectable, safe helmet that meets the Standards. Pick a good one that fits properly, and take good care of it.

1. Measurement

Measuring the head is a starting point for the entire sizing procedure. Due to varying shapes, heads that are apparently the same size when measured by a tape may not necessarily fit the same size helmet. A small metal tape measure, or a cloth tape may be used to make your initial measurement. The circumference of the head should be measured at a point approximately one inch above the eyebrows in front, and at a point in the back of the head that results in the largest possible measurement. Take several measurements, to make sure you have the largest one.

2. Try-On

Once you've determined your preliminary tape measurement, select the helmet that is closest in hat size to the tape measurement. If it is between sizes, round-up to the next largest size. Now try on your helmet. If you are not familiar with helmets, you should use these instructions on the proper procedure for putting one on:

1. Grasp the helmet by the chin straps, with the front of the helmet facing you and the top of the helmet facing down.
2. Place your thumbs on the inside surface of the straps and balance the helmet with your index fingers.
3. Spread the helmet apart with your hands, and slip it down over your head.

Helmets of different shapes go on differently. Sometimes, the front of the helmet must go on first; other times, the rear. If the helmet flops down on your head with no resistance, you have your first indication that it may be too large. Obviously, if it won't slide down over your head at all, it is too small.

Many people unfamiliar with helmets are reluctant to pull down if they meet resistance as the helmet goes on. To tell if it is really too small, or just snug going on you should continue the effort to get the helmet on. Only if the helmet is impossible to put on should you move up to the next size, as helmets that go on snug generally fit very well once on all the way. Remember, most people will select a helmet that is too large for them. They will regret it later, because ill-fitting helmets are more likely to be noisy, windy and fatiguing to wear. We have noted that some people have a tendency to wear a helmet perched on the backs of their heads, like hats. Be sure that the helmet is sitting squarely on your head. Use the location of the eyes in the eyeport of a full face model as a gauge. The eyes should be approximately in the center, with the top edge of the liner padding just above the eyebrows.

3. Checking Horizontal and Vertical Movement

Now that you are wearing the helmet, use a mirror to look carefully at the way it fits. Check to see if the cheek pads are in contact with the cheeks. Is there excess pressure on the cheeks? Look for gaps between the temples and the brow pad. Check the back of the helmet where the neck roll (if the helmet has one) makes contact with the neck. Does it touch at all? Or is it pushing the helmet away at the rear, causing it to roll down over the eyes in front? After you have made your visual check, grab the helmet in your hands - one on either side -and try to rotate the helmet from side-to-side. Note any movement of the skin while doing this, as well as the amount of resistance to movement. Hold your head steady to do this. Next check movement up and down, again noting skin movement and resistance. If in either test there was little or no skin movement, and/or the helmet moved very easily, the helmet is too large. It is important to note here that you should think about the comfort of the helmet during the fitting process - with respect to comfort, pressure points, or anything else that will help you make the right sizing choice. A properly fitted helmet will cause the skin to move as the helmet moves. And, it will feel to the wearer as if evenly distributed pressure is being continuously exerted around the head.

NOTE: Helmets are a little like shoes, in that they do break in a little. For this reason, the best attitude to have when fitting is that the helmet should be as tight fitting as you can stand to wear it - taking into consideration the length of time it will be worn. For Example: A drag racer's helmet can be very tight, because it will only be worn for a few minutes at a time. On the other hand, a police officer, who wears a helmet for hours at a time is more concerned with comfort.

4. Retention Check

Now fasten the chin strap, so you can check it. After the strap has been tightly fastened, hold your head steady, and note that this test may be a little uncomfortable, but that it is very important. Reach over the top of the helmet, grabbing the bottom edge with your fingers. Then try to roll the helmet off your head. If it comes off, it is undoubtedly too large.

NOTE: Do not use a helmet that can be rolled off the head with the strap fastened! Try not to cause severe pain, but do give a good, strong pull on the helmet. THIS TEST IS VERY IMPORTANT.

5. Pressure Point Check

Finally, unfasten the chin strap and remove the helmet. Immediately after the helmet has been removed, use a mirror to observe the coloration of the skin on the forehead and cheeks. A reddening of the skin in a small area may indicate a pressure point. Pressure points sometimes are not noticed by the wearer until after several minutes, or even hours of wear. They sometimes cause headaches and are, at the least, uncomfortable. If you notice a pressure point, note if you experienced discomfort in that area while wearing the helmet. If you can't remember, put the helmet back on for a few minutes, paying particular attention to the anticipated pressure point(s). If the pressure point discomfort continues, go to the next largest size, repeating steps three, four and five.

Confirming Proper Fit

One way to confirm your evaluation of proper fit is to try on helmets that are one size larger and one size smaller than the one you think is right. Keep in mind that people gravitate towards larger sizes. Another way, is to wear the helmet around the store for a few minutes. This will allow any pressure points to show up.

WARNING: No helmet can protect the user from all foreseeable impacts. For maximum protection, a helmet must fit securely and should provide adequate peripheral vision. The chin strap must be securely fastened.