One of the first pieces of safety gear we buy — if not the first — is a helmet. But you need to get one specifically for car racing because there are key differences between those manufactured for motorcycling and those for car racing. To find out the current state of the art in helmets and the helmet industry, we caught up with Kyle Kietzmann, president and COO of Bell Racing USA, a leading helmet manufacturer in Champaign, Ill.
With a motorcycle helmet, the eye port size is different, with a wider field of vision. Motorcycle helmets also are certified to a couple of different standards, Kietzmann said. The first testing standard is from the DOT and then there is the Snell Foundation M standard. Naturally, M stands for motorcycle. The Snell SA standard, as in the current SA2010 rating required to race with NASA, stands for special application.
“There are also some differences in terms of the tests, because with the automobile helmet there is a roll bar test and an additional anvil test,” Kietzmann said. “Also with the auto racing helmets, there’s a fire component to it, a fire test that they have to be certified to. Basically, it’s a self-extinguishing test. You’ve got to introduce flame to the helmet and it has to extinguish itself in 30 seconds after removing the flame.”
Another test motorcycle helmets don’t have to endure is for the attachment points for head-and-neck-restraint devices. The anchor points are tested to ensure they are positioned properly and, of course, tested under tether load to ensure the anchor points don’t pull through the shell. Also, some motorcycle helmets are made with injection-molded shells, which wouldn’t pass any sort of an auto helmet standard.
Kietzmann said the biggest advances in helmet technology over the last decade or so have come from advanced materials in the outer shell, improved manufacturing techniques such as compression molding, and new liner materials.
In terms of the outer shell, most auto racing helmets are built using laminated composites such as fiberglass, carbon fiber, Kevlar or some combination of those materials.
“The introduction of carbon materials has been a big advance, and then compression molding also has been a big advance for the helmet,” Kietzmann said. “When I started, for the most part, everything was hand lamination and now it’s transitioned to some form of compression molding.”
In a compression-molding system, an assembly worker begins by treating the inside of the mold with a release agent, which comes in powder, gel or spray forms, and they assist in popping the part out of the mold after it’s cured. Once the release agent is applied, the worker applies the layers of fiberglass, carbon fiber or Kevlar to the form, depending on the helmet’s lamination schedule. As is often the case with auto racing helmets, the composite materials are pre-impregnated with the right amount of resin. The mold, which is often two-pieces, but can be as many as three or four pieces, closes around the form, which distributes the resin to the right places, forms the shell and applies heat to cure it all in one step.
“In the old days, you would do a hand lamination process, then take the part out of the mold and put into an oven to cure,” Kietzmann said. “In this case, you’re kind of combining both of those stages where you’re laying the laminate, but then also curing the shell at the same time. It gives us a product that stronger and more consistent with lighter weight. It functions better. Also, from an environmental perspective, it’s a cleaner process.”
Inside the helmet, liner materials also have improved. New bead and liner materials do a better job managing energy and have natural rebound tendencies, so they’re useful for single and multiple impacts.
Those advances have allowed the FIA to develop a standard of its own called FIA 8860, which requires certification to the Snell standard and additional shell hardness test and an additional impact from 5 meters that measures another level of energy management in the helmet.
When it comes to choosing a helmet, Kietzmann notes, your racing application matters. Criteria for selection include whether you’re in an open or closed car and whether your helmet needs aero to prevent buffeting or ventilation devices to feed fresh air into it. However, fit is the most important element in helmet selection.
“You may do a head measurement and they’re a 58, but they say the 60 or the 61 feels a lot more comfortable, but in reality it’s mis-sized,” Kietzmann said.
Measure your head determine your size with the helmet manufacturer’s sizing chart. When you put it on, a good test of fit is whether you can rotate your head inside the helmet. Grab the face bar and try to turn your head inside the helmet. Your head should be nice and snug and not turn inside the helmet. Also, realize that helmets don’t last forever, even if they haven’t been involved in a crash.
“We do recommend that you replace a helmet every three to five years,” Kietzmann said. “Not only do you take advantage of newer construction and newer materials that are being used, but also you can’t always tell or know how many times a helmet has hit a roll bar or how often you’ve banged it getting out the car or whether someone has dropped it. A helmet is designed to delaminate and compress the liner and absorb energy, and the more times you do that, it’s going to decrease its ability to manage energy.”