What is the primary function of a helmet? Many believe it is to absorb impact energy, which is understandable considering that the long standing focus of helmet standards is impact absorption. However, while certainly important, attention should not be limited only to impact absorption.
In official standards the force, angle and impact position of test impact forces are clearly defined and specified. But these impacts take place under controlled laboratory conditions, and are limited by the size restrictions of functional helmet design.
What if a helmet is faced with severe impacts in the real world? Even helmets that pass the highest impact absorption standards in the world have limits. To help cope with these limits, another helmet feature has to work together with these impact absorption properties.
We are talking about the capacity of a helmet to glance-off obstacles and to slide across uneven surfaces, to minimize the chance of being caught by obstacles. We refer to this attribute as “glancing off”.
Physics teaches us that kinetic energy increases in proportion to the square of speed (simply put, the faster you go the more energy you carry). Therefore impacts in real world accidents can carry energy levels that are well above established standards. This suggests why “glancing off” is so important in the real world.
In fact, Arai’s long history of studying numerous incidents has led to a simple observation: “The higher the energy, the higher the need for glancing off objects”. This in turn results in the conclusion that “glancing off” can allow for better “impact absorption” capacity of a helmet. ”The more energy you can avoid sending into the helmet, the more absorption capacity the helmet has in reserve”.
The minimum official “impact absorption” capacity of helmets are set by the established international standards such as ECE or DOT. However, there is practically no standard defined or enforced to insure any level of “glancing off” properties.
The capacity of a helmet to “glance off” an object is therefore completely dependent on the manufacturer. Arai believes this “glancing off” factor brings about a big difference in protective characteristics in real world circumstances.
Strange as it may sound, this fundamental functioning of a helmet needs to start with an evaluation of the nature of the manufacturer.
One of the most distinctive features of an Arai helmet is the comfort it offers. How comfort is experienced is however a very personal matter. Therefore it is very difficult to compare the comfort offered among different helmet brands. Yet, there are strong arguments that indicate that the comfort offered by an Arai helmet is in a class of its own.
The most convincing in this respect are the statements offered by racers. Racing drivers and riders must concentrate themselves for significant amounts of time under extreme conditions. High temperatures, fierce competition, tightly strapped to their seats and still able to focus completely on racing as fast as possible.
That is why for instance Formula 1 racing drivers need that ultimate comfort because nothing may distract their concentration. In fact, F1 drivers may well be the most demanding racers where comfort is an issue. They do not choose a specific helmet brand for safety performance only. The fit and balance of the helmet is crucial for them as well. What is then the helmet of choice for most of the Formula 1 grid? They prefer Arai. And so should you, as every helmet wearing the Arai name is made by the very same team that builds yours.
The explanation why, is simple: the approval is based on minimum test requirements. For many manufacturers they are satisfied to only meet these minimum test requirements. There is also a limit to the capacity of any given helmet to absorb impacts. However, there is are no limits outside of the test lab. These circumstances just cannot be simulated under test laboratory conditions, as they are much more demanding than any standard.
At Arai we have studied incident data for decades. We have gained an incredible knowledge in our many years of racing on the highest levels. From MotoGP to Formula 1 Arai is the favourite choice of riders and drivers and this offers us a wealth of personal and hands-on data from our racers. We have learned not to focus on just meeting these laboratory test standards. Standards merely verify that the helmet complies with minimum test requirements. Nothing less, nothing more.
But meeting these standards is not a goal on itself. Not for Arai. For us they are a starting point, a marker for further developing and improving our helmets.
To understand how helmets function, a little bit of physics is helpful. For the laboratory tests, a test speed of only 28 kilometres per hour is used. This is about the speed of a fast bicyclist. Not a very realistic speed for motorcycle use. And under real world circumstances, there is not limit whatsoever to the severity of a single impact or even multiple impacts. Real world circumstances are simply much more demanding than any test lab standards can simulate.
OK, what would happen if we increase the test speed then to say, 100 km/h? The results are spectacular: when the speed is increased by a factor 4, the impact energy will increase with a factor 4^2 = 16! No helmet is able to sustain such an direct impact or guarantee absolute protection. Not even an Arai helmet.
The wearer of the helmet may be moving much faster than the drop speed of the impact tests. Still in the real world, riders walk away from crashes at even much higher speeds. How is that possible? By minimizing the impact energy that is directed into the helmet. This is realized by letting the helmet to slide over and to glance off objects.
It’s important to know that the impact energies the helmet needs to absorb may be dramatically reduced if it can glance off obstacles and slide across uneven surfaces, diverting impact energies.