Trek and Bontrager unveil WaveCel brain-saving helmet technology

by James Huang

Trek recently created quite a stir with a rather hype-heavy social media campaign that teased “Cycling’s most important change in 30 years.” As expected, wild speculation ensued, including from our own Dave Rome. Was it a new frame technology? Some sort of crazy bike? Something e-related?

As it turns out, Trek’s big news is a new energy-absorbing helmet material called WaveCel. That perhaps won’t be as exciting as some of the alternatives that have been proposed (which haven’t been disproved, I should point out), but if the company’s claims about how WaveCel can dramatically reduce the incidence of concussions is true, it’ll indeed be a pretty big deal.

At first glance, WaveCel is just Trek and Bontrager’s interpretation of the fluorescent green Koroyd polymer honeycomb helmet liner already in use for several years by Smith, Endura, and others, but with a different cell shape and a different day-glo hue. And just like Trek and Bontrager are claiming now, Koroyd also touted significant reductions in the incidence of traumatic brain injuries for riders wearing Koroyd-equipped helmets, by as much as 58% in the case of Koroyd.

WaveCel may look a lot like Koroyd, but Trek and Bontrager say that that’s as far as the similarities go.

Koroyd’s ability to dissipate impact energy is reliant on how that polymer honeycomb compresses, much like what happens to an empty beer can when you step on it. According to Koroyd, that fancy honeycomb is not only able to absorb more total energy than conventional foams of the same thickness, but it also reduces the peak forces transmitted to the rider’s skull and brain. And because there’s so much flexibility in how the material is constructed (such as in cell diameter and material densities), Koroyd can also be strategically tuned for different areas of the helmet.

WaveCel supposedly does all of that, too, and more. And it’s that “more” that Trek and Bontrager say is the key to its impressive-sounding safety performance.

WaveCel cells absorb energy via crumpling just like Koroyd, but the clever geometry of the cells also allows it to initially flex upon impact. If Koroyd is like a bunch of plastic straws glued together, WaveCel is sort of like a grid of plastic playing cards. According to Trek and Bontrager, that unique geometry lowers the force threshold at which the material begins to act, further reducing transmitted forces relative to Koroyd or conventional foam helmets.

Moreover, the smoother profile of WaveCel is said to impact rotational protection similar to conventional MIPS liners — meaning that WaveCel helmets not only provide similar benefit, but don’t require an additional layer of plastic next to your head.

WaveCel isn’t any thicker than traditional foam liners, either, so WaveCel-equipped helmets are still as low-profile as usual. EPS is still used as a sort of intermediate-level liner, however, to help the helmet maintain its shape in day-to-day use and hold it together during a crash.

Taken in total, WaveCel helmets aren’t said to just prevent more serious injuries like skull fractures or major traumatic brain injuries; they will supposedly reduce the incidence of concussions in general to less than 1-in-50 for “common cycling accidents”.

“SLIP helmets significantly reduced rotational acceleration compared to CONTROL helmets in all impact scenarios, with reductions ranging from 21% (30° slow impact) to 44% (45° slow impact),” stated a paper published in the scientific journal Accident Analysis and Prevention, and co-authored by orthopedic surgeon Dr. Steve Madey and biomechanical engineer Dr. Michael Bottlang, both of whom worked with Trek and Bontrager to bring WaveCel to cycling helmets. “CELL helmets significantly reduced rotational acceleration compared to CONTROL helmets in all impact scenarios, with reductions ranging from 34% (60° slow impact) to 73% (45° fast impact).”

Most government-mandated testing only takes into account direct linear impacts, not rotational forces that are induced on more glancing blows like what is depicted here. Photo: Accident Analysis and Prevention.

Third-party independent testing from Virginia Tech University (VTU) hasn’t yet verified these specific claims, but it’s worth noting nonetheless that production samples of the new WaveCel helmets have all earned top five-star ratings. It’s also worth pointing out that while US helmet safety tests don’t incorporate rotational elements into the requirements, VTU’s test protocol does, and so helmets with some level of rotational protection tend to score better than those without.

Before you get too excited, even the paper’s authors are careful to point out that it’s too early to declare WaveCel a panacea for every bike-related crash, and while the “nearly 99 times out of 100” claim is worthy of attention, there are limits.

“The results show potential in reducing the risk of rotational TBI [traumatic brain injury],” the paper states. “Furthermore, the results suggest that the efficacy by which the SLIP and CELL technologies provide improved protection depends on the impact angle and impact velocity. Since these findings are limited to a specific combination of impact speeds and impact angles, further investigations are warranted to explore higher impact severities accounting for bicycle falls at higher speeds and for collisions with automobiles.”

Bontrager will offer WaveCel in four new helmet models: the aero-minded XXX WaveCel (US$300, 325-390g, US version, depending on size), the more all-purpose Specter WaveCel (US$150, 322-380g), the Blaze WaveCel trail helmet (US$300, 380-448g), and the Charge WaveCel (US$150, 392-448g) for urban and commuting applications. International prices and weights are to be confirmed.

Safety first, but the other stuff matters, too

Taken at face value, WaveCel is a genuinely big deal. Crashes are fairly common in cycling, as are concussions. Even if you haven’t had to deal with a concussion yourself, chances are good that someone near to you has. Countless lives have been altered as a result of brain injuries that might otherwise have been prevented. If WaveCel is as good as Trek and Bontrager say it is, I almost wish Legacy Research Institute – the company founded by Drs. Madey and Bottlang that developed and own the WaveCel technology – would just give it away.

That’s not how the world works, of course, and Trek and Bontrager currently have a multi-year exclusive agreement with WaveCel. Madey and Bottlang did confirm that other companies involved in other sports are open to licensing WaveCel, however, and once Trek and Bontrager’s agreement expires, chances seem good that we’ll see it incorporated into other cycling brands.

But as much as safety should always be the primary criterion by which people make their helmet buying decisions, it’d also be foolish to pretend like secondary features, such as weight and ventilation, don’t play a major role as well. I’ve also found many Koroyd-equipped helmets to be relatively poorly ventilated given the radial orientation of the plastic cells and the lack of internal channeling, for example, and WaveCel is little changed in that respect.

Astute readers will also notice that all of the new WaveCel helmets are a little weighty, and even Bontrager admits that WaveCel will add about 50g relative to a conventional EPS foam helmet.

The open nature of WaveCel should make it very easy for heat to dissipate from a rider’s head. But that said, you can also easily see how a lack of internal channeling will hinder flow-through ventilation, which is more important for keeping a rider’s head cool when they’re moving. Photo: Bontrager.

In any event, I don’t intend to voluntarily slam my head into the pavement for the sake of product testing, but I’ll at least be able to check out these secondary features firsthand soon enough. All of these new helmets are available immediately, and I now have production samples in hand.

Either way, it’s good to see the needle moved in this way, particularly given the importance of the subject matter. Nicely done, Bontrager — but maybe turn down the hype machine a little next time, eh?

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