A New Twist on Motorcycle Helmet Safety From 6D

How highly do you value your brain? In the classic 1973 comic science-fiction film Sleeper, Woody Allen’s character shouts out: “My brain? It’s my second favorite organ!” Given such an authoritative source, you gotta figure your brain ranks pretty near the top. Which is why smart motorcyclists always wear helmets.

It’s fair to say helmets have developed gradually, with new composites technologies—including carbon fiber, Kevlar, and even tried-and-true fiberglass—and innovative ways to build less-expensive plastic helmets emerging over the years. We’ve also seen new face-shield technologies emerge, and integration with Bluetooth audio systems remains a fast-growing part of the market.

But the core components of the modern motorcycle helmet remain largely the same: a stiff(ish) shell meant to prevent penetration with a collapsible liner meant to absorb crash forces. It’s here, with the use of expanded polystyrene (EPS) liners, that the state of the art is more aptly described as the tried and true.

But there’s significant new thinking in the field from 6D Helmets, with its Omni-Directional Suspension (ODS). Think of ODS as a suspension system fitted into the helmet liner to reduce shock energy transmitted to the brain under impact. Elastomeric isolation dampers serve as the key element. Depending on helmet size and type (street or dirt), between 26 and 29 of these rubbery little hourglass-shaped nubs sit between the layers of the multi-part EPS liner.

Bob Weber, co-founder and CEO of 6D Helmets explains, “By separating the helmet liner into two parts, we have the outer EPS layer mated to the shell and the inner layer up against the wearer’s head. On impact these separate layers have the ability to compress and come together. They can shear omni-directionally within themselves, reducing angular acceleration, and we gain superior low-energy performance from the ability of the suspension action on lesser impacts. By having a suspension system in the helmet, the helmet is active at a much lower energy demand than a traditional helmet design. And if the energy is high enough, the layers come together and the EPS takes over.

“Another significant benefit of our ODS system is simply time,” Weber continues. “By allowing the inner liner to travel within itself, we add time into the impact event equation. If you take any given impact and stretch it over more time, you’re basically going to reduce the severity of that impact.”

And how does spreading the transfer of force over time help the rider? Remember your basic physics: F = ma, or force equals mass times acceleration. Slow down acceleration and you reduce force. Co-founder and Director of Engineering Robert Reisinger explained it in simpler terms: “The broader range of protection that our ODS technology offers to your brain, due to its ability to mitigate impact force over other helmets at low, medium, and high velocities, is like the difference between jumping off a bridge with a bungee cord or jumping with a rope. ODS offers more time to arrive at peak G-force in lab tests.”

Once these dampers bottom out, the separate portions of the crushable EPS liner come into contact, deforming to absorb energy in the manner of conventional helmets. 6D also incorporates outer composite helmet shells constructed of a strong layered blend of carbon fiber, aramid fiber, and fiberglass—again, very similar in design and action to many other premium conventional-style helmets.

Extensive testing conducted by an independent, third-party laboratory clearly demonstrated the effectiveness of the ODS helmet design alongside a wide variety of other leading helmet brands—more on those head-to-head comparisons shortly. 6D went on to have their helmets certified to US DOT FMVSS 218 standards (for the US) and ACU standards (used in the UK), plus the ECE (Economic Commission for Europe) standard 22.05 recognized by more than 50 countries and most competition organizations.

That’s an impressive array of approvals, but noticeably lacking from this list is the widely recognized Snell 2010 certification. When we asked why that standard was absent, Weber and Reisinger explained they strategically designed 6D helmets to be more effective during real-world impacts rather than focus on the Snell 2010 benchmarks. The prime issue concerned Snell’s double-strike test, wherein the helmet is subjected to high-energy impacts twice in the same spot. Performing at that double-strike level creates a helmet that is too stiff, Weber and Resigner feel, so much so that it limits the capability of the EPS liner to function adequately at low-threshold energy demands.

Generally speaking, low-threshold impacts are defined as those created at or under 4 meters/second—below the values set by various testing standards. Yet that 4 meters/second level is about twice the energy necessary to inflict a concussion in an adult male and would also describe a huge percentage of impact levels in real-world motorcycle crashes.

High-velocity tests, in comparison, run from 6 meters/second up to as high as 7.75 meters/second in some tests—that’s really extreme stuff, perhaps so high as to become somewhat immaterial to motorcyclists in most cases. According to the company, 6D helmets function as well as or slightly better compared to conventional helmets in high-velocity tests, but low-threshold impacts are where they really excel.

Angular acceleration is defined as the rate of change of angular velocity over time or energy generated from oblique angle impacts—glancing blows rather than a blow squarely perpendicular to the helmet surface. Growing consensus within the medical community finds that angular acceleration energy is a primary cause of concussion, mild-traumatic brain injury (MTBI), and traumatic brain injury (TBI). The result of this type of impact, and subsequent energy transfer therefrom, is shearing, tearing, compression, and rotations of the brain within the skull.

Testing shows that 6D’s ODS technology dramatically reduces the transfer of angular acceleration energy compared to conventional helmets, resulting in less force transferred to the brain, which may reduce the likelihood of concussion or brain injury. ODS starts working the instant any force is applied to the shell, lowering peak acceleration and also spreading it out over time, which makes the helmet much more compliant and progressive in action.

6D’s technology has found suitors outside of motorsports too. In recent years, another group has gotten serious about addressing the causes, severity, and long-term effect of concussions—the National Football League. They’re serious about pursuing answers, working hard to advance development of technologies that can improve brain protection. They’ve committed up to $20 million to fund innovative solutions through their Head Health Initiative, which includes three Challenge topics. Challenge III began in 2016 to stimulate development of materials that provide excellent energy-absorbing and energy-dissipating properties. Of 125 applicants, five winning companies advanced in Round 1, each receiving $250,000 to work on developing state-of-the-art materials. One of the winners was 6D Helmets, the only helmet manufacturer selected.

The MIPS Solution
In Sweden, neurosurgeons, research scientists, and engineers collaborated to create the Multi-directional Impact Protection System, or MIPS, to allow helmets to better protect the human brain. This technology was created to reduce rotational forces on the brain caused by angular impacts. With MIPS, a low-friction layer placed between the liner and helmet shell allows the helmet to slide relative to the head during impact. Testing shows that rotational acceleration could be reduced by up to 39 percent without altering energy-absorbing properties in direct, radial impacts. In 2014, MIPS AB entered into a partnership with BRG Sports, parent company of Bell Helmets and other helmet companies. In addition to Bell, MIPS technology is now available in a wide variety of motorcycle helmets, including Fox, Fly, Answer, MSR, and O'Neal.