Trendy bike helmets usually include a myriad of claims. On condition that many premium choices are designed with bike racing in thoughts, these are sometimes performance-related. The finest bike helmets purport to be extra aerodynamic or higher ventilated, and so they definitely are getting lighter, however are they any safer?
It’s a good assumption that if you purchase a helmet it’s match for objective. All helmets offered by professional retailers can have handed a security normal for the precise nation it is offered in. Within the US it’s the SNELL normal, whereas within the UK and Europe it’s EN 1078 and also you’ll see a sticker on the helmet to confirm that it meets the necessities.
However provided that these requirements haven’t been up to date for 25 years, are they nonetheless proof sufficient that the helmet we’re shopping for is secure? I requested Dr. Mazdak Ghajari, lead researcher of the HEAD Lab challenge at College Faculty London, which as a part of its research has examined quite a few bike helmets with a view to offering customers with extra in-depth information, whether or not the present normal had been ample?
“Requirements be certain that helmets meet a naked minimal safety degree. They’re historically designed to guard towards sure accidents, primarily cranium fractures. Therefore, helmets that meet requirements, in distinction to people who don’t, have a minimal degree of safety,” he stated
“Present requirements measure helmet safety throughout impacts towards ‘inflexible’ flat or non-flat (hemispherical or curbstone) anvils. Their go/fail is predicated on the chance of cranium fractures. Consequently, present helmets present good safety towards cranium fractures and related focal mind accidents akin to contusions.”
Three anvils utilized in helmet testing
(Picture credit score: Future (Joe Baker))
However cranium fractures aren’t the one potential head damage that may be attributable to falling off a bicycle. So are these requirements just a little too slender of their strategy? Dr. Ghajari believes so.
“These requirements don’t take a look at helmets for mitigating rotational results of impacts on the mind. Head rotation can produce accidents akin to diffuse axonal accidents, which have long-term results and are sometimes harder to handle than focal mind accidents,” he says.
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In fact, producers of helmets can design a product that exceeds the required necessities to satisfy these requirements. And it’s right here that we’ve seen the creation of know-how designed to minimise the rotational impacts that Dr. Ghajari references, with MIPS [Multi-directional Impact Protection System] being essentially the most recognisable. As a non-proprietary design, it’s seen throughout many helmets from many manufacturers. However what is strictly meant by a rotational impression and why has it been such an space of focus prior to now few years?
“Head impacts have totally different mechanical results on the top. They will apply a direct drive to the top, which might fracture the cranium. These results are sometimes assessed by measuring the ‘linear acceleration’ on the centre of mass of the top. Because of this it’s well-acknowledged that present requirements, which measure peak linear acceleration, assess the chance of cranium fractures,” he says.
“However head impacts may also produce head rotation. Head rotation can produce shearing of mind tissue and result in bleeding and axonal accidents.” Axonal accidents are when the mind’s nerve fibres are torn, usually attributable to the mind shifting and rotating contained in the cranium throughout an accident.
(Picture credit score: Future)
Dr. Ghajari explains that any impression may cause each linear and rotational head motions, however that some impacts produce bigger rotations. An instance of that is an indirect impression, the place the route of movement is at an angle to the impression. “As a result of they [oblique impacts] produce a big drive tangential to the helmet, they have a tendency to extend helmet/head rotation,” he says.
So does MIPS know-how – or comparable choices – make a helmet safer?
“Utilizing applied sciences devoted to decreasing head rotation throughout impacts are useful in bettering helmet safety,” says Dr. Ghajari. “For example, applied sciences that permit for bigger relative rotation between the top and helmet will help cut back head rotation and MIPS has been efficient in decreasing head rotation in indirect impacts in laboratory experiments.”
(Picture credit score: MIPs)
Whereas MIPS has been proven to enhance the security of a helmet as regards to decreasing head rotation, it’s been integrated into designs that in any other case seem largely unchanged from these of the final 5 and even ten years. Bike helmets proceed to make use of a reasonably standardized design – an outer shell made out of a tough plastic, an internal lining made out of foam, an inside adjustable ‘cage’ that enables the helmet to be tightened and a chin strap. It begs the query if this blueprint stays the very best strategy from a security perspective. Once more, I requested Dr. Ghajari his ideas on
“For my part, it’s a good design by way of security,” he says. “The outer shell gives some safety towards sharp objects, and it spreads the contact drive over a bigger space of the internal liner. This helps to have interaction a bigger quantity of the liner, thus growing the power absorption. The adjustable cage system could be very helpful in ensuring that the helmet is secured to the top and doesn’t come off earlier than the impression.”
The ‘blueprint’ of a tough outer shell, an internal foam liner and a chin strap stays the usual strategy for a secure helmet.
(Picture credit score: MichelleArthursBrennan)
It’s encouraging to listen to, particularly from the lead in a research that has examined some 30 helmets with a view to offering the buyer with detailed, impartial data concerning helmet security (you will discover the outcomes at hiperhelmets.org). However that’s to not say designs can’t be improved and that helmets gained’t proceed to evolve. For instance, Trek at the moment has a patent software for a helmet design that makes use of a ‘sliding power diverting layer’ that additionally acts because the outer shell of the helmet.
Dr. Gharaji acknowledges that present linear and rotational impression safety may be improved upon provided that cyclists nonetheless maintain mind accidents after falls and collisions, and can possible come on account of a change in materials. So long as it could actually show to be cost-effective.
“There have been a number of efforts to include new supplies in helmet liners to enhance head safety, however they’ve largely didn’t enter the market on account of both marginal enhancements or excessive prices,” he says. “I hope to see new supplies integrated in helmets that may enhance their safety with out having a big impression on helmets’ value.”
It’s a legitimate level and one which’s integral to the persevering with improvement of safer helmets. Helmets have to be wearable and eradicating boundaries to make use of is a crucial issue, whether or not it’s making them extra inexpensive, lighter or transportable, such because the foldable Newlane design.
The Newlane helmet is created to be packable and transportable
(Picture credit score: Newlane)
I’ve at all times favoured helmets which have felt mild on the top and have discovered them, unsurprisingly, to be way more wearable than ones which can be extra weighty. It’s a calling card of many highway helmets, which extol the air flow and total lack of weight. However I puzzled if these trendy, light-weight designs are much less secure, even when they’re extra fascinating?
“To enhance air flow, holes are integrated within the helmet design, which suggests extra of the liner is eliminated, thus decreasing the quantity of liner accessible for power absorption,” says Dr. Gharaji.
One other newer development in helmet design has been the incorporation of aerodynamic properties. Once more, I used to be to search out out if this may need a detrimental impact on the security of the helmet?
Closely vented helmets imply a cooler head however a discount within the quantity of liner foam used
(Picture credit score: Tyler Boucher)
“Aerodynamics and air flow put constraints on helmet design from a safety perspective,” says Dr. Ghajari. “Aerodynamic helmets are thinner, however the thinner the helmet, the much less liner is offered for power absorption. There could also be smarter methods for designing helmets for higher aerodynamics and air flow, which contain eradicating a part of the liner however in a method that may contribute to higher safety towards sure damage mechanisms, akin to rotational mechanisms,” he provides.
“At present the dominant strategy for bettering aerodynamics and air flow is thinning the helmet and incorporating holes within the liner,” Dr. Ghajari concludes.
A contemporary aero design within the form of Trek’s Ballista helmet
(Picture credit score: Charlotte Broughton)
In fact, this doesn’t make aero or light-weight helmets unsafe, however making a helmet thinner or including vents, which necessitates eradicating areas of the liner, will make bettering security more difficult. That is the place thorough, impartial testing that considers real-world impacts will help solidify client confidence.
To some extent the Virginia Tech scores, which gives comparable outcomes throughout a variety of helmets and is totally freed from any funding or affect from helmet manufacturers, provide this. Nonetheless, a fast scan of the 250+ helmets that it has examined up to now reveals that many obtain the complete 5 stars. Whereas that is encouraging by way of the helmet’s security, it could possibly be urged that there’s a must proceed to advance the testing, as Dr. Gharaji and his group are doing, which in flip would require the helmet designers to evolve as effectively if their merchandise are to obtain the very best security scores.
