Bicycle helmets are one of the most important pieces of equipment in a cyclist’s armoury and provide an essential function in protecting a cyclist’s head when they become dismounted. There are all kinds of helmet innovations on the market which are designed to make cycling safer and more convenient.
Trek and Bontrager have been working on a new helmet technology called WaveCel, which they claim is the biggest advancement in the protection against cycling concussions.
What is WaveCel technology?
Before understanding how this technology works, we must first look at standard bicycle helmets and other helmets which mitigate rotational head acceleration.
Standard bicycle helmets have a lining of rigid expanded polystyrene foam (EPS), which provide great protection against skull fractures and traumatic brain injury.
Other designs, such as the Multi-directional Impact Protection System (MIPS), operate by adding a low friction layer between the helmet’s shell and the liner. This goes one step further than the standard EPS helmet in reducing rotational motion when involved in an accident.
Koroyd have also taken protective designs further in creating a co-polymer tube structure for helmets which absorbs and decelerates the energies resulting from an impact to limit the risk of skull fractures and traumatic brain injury.
According to the Trek website: “WaveCel is a collapsible cellular material that’s incredibly effective at preventing concussion caused by common cycling accidents.” WaveCel helmets come with a cellular liner designed to absorb the force of impact before it reaches your head. Combining the approaches of MIPS and Koroyd, the cellular structure adopted by Bontrager mitigates the initial impact and any rotational energy.
What’s the deal with rotational acceleration?
Linear acceleration and rotational acceleration are often discussed in relation to cycle helmets and it is hotly debated over which one causes concussion.
Linear acceleration usually occurs where there is a sudden impact to the head. For instance, where someone is thrown from their bike, the linear acceleration occurs when the cyclist hits the ground. There is an obvious risk of brain injury in these circumstances.
Rotational head acceleration is common during an impact and occurs where an impact causes the head to rapidly spin, therefore carrying a risk of brain injury. The study into WaveCel technology suggests that this rotational acceleration is likely to cause concussion.
After comprehensive research, Bontrager have claimed that WaveCel technology is 48 times more effective at preventing concussion than a standard EPS lined helmet, because it reduces the risk of rotational acceleration.
Competition on the market
Despite looking like an amazing development, this technology appears to be under fire from some of WaveCel’s competitors, namely MIPS and Koroyd.
MIPS has tested the WaveCel technology, using the same tests that Bontrager performed, and has failed to replicate the results instead finding results far below Bontrager’s claims. In their tests, MIPS found that there was no difference in risk injury reduction between WaveCel and EPS helmets at an impact speed of 4.8 m/s (around 11mph) and only a slight difference when testing the helmets at 6.2m/s (around 14mph).
MIPS attributes this difference in results to the testing dummy which Bontrager used, stating that the testing dummy used is not commonly used to test bicycle helmets. In their opinion, the claims made by Bontrager are impossible to substantiate, as no two crashes are the same and no two people are the same.
Although MIPS feel encouraged that more people are looking into ways to reduce the rotational motion after a collision, there are still concerns regarding the lack of any standard to test these kinds of helmets.
Koroyd has also voiced scepticism at the safety claims of Bontrager regarding WaveCel, mainly focusing on the importance of mitigating linear acceleration.
Unlike linear acceleration, rotational acceleration still remains unaddressed by international standards surrounding head protection. Koroyd make note of the fact that rotational acceleration presents a risk of injury to the brain but is substantially reduced as a by-product of reducing linear acceleration.
Koroyd also claim that circular structures are proven to be the most efficient energy absorbers, which led them to create their Koroyd helmet liner. According to Koroyd, their structure exhibits significantly higher energy absorption capabilities than other materials and so helping to mitigate rotational acceleration through the reduction of linear acceleration.
Does that mean it’s all bad?
Of course, competitors are going to have differing opinions on which helmet is the best, but one thing they do seem to agree on is that rotational acceleration is harmful and that there needs to be an objective industry standard to which it can be compared.
WaveCel has effectively combined both MIPS and Koroyd technology to make something that can deal with linear and rotational accelerations. Whether the technology proves to be useful or not remains to be seen.
Bontrager has responded to these criticisms, stating that slip liners are a good technology that provide a real benefit to riders, but that there is also room for innovation in rider safety. They have elected to leave the choice in the hands of the consumer and will continue to stock helmets which have EPS, MIPS and WaveCel.
Whichever you decide is best, the advantages of wearing a helmet definitely outweigh the consequences of going without, so no matter the distance, remember to wear a helmet while you’re on a ride.