To understand how a helmet functions, or should function, understanding a little bit of how physics works is always going to be more than helpful. For the laboratory tests in the Arai facility, the official standard test speed of only 28 kilometres per hour is used. This is about the speed of one of those rider propelled acoustic motorcycles that keep getting in my way when I commute through the city. This can hardly be regarded as a very realistic speed for motorcycle use. Under real world circumstances, there isn’t any sort of limit whatsoever to the severity of a single impact or, even worse, multiple impacts. Real world circumstances are simply much more demanding than any test lab standards can ever simulate.
So what would happen if the test speed were increased to 100 kmph? The results are spectacular. When the speed is increased by a factor four, the impact energy will increase with a factor of four squared. If you had difficulty with Junior Cert mathematics then that’s 16 times the energy sent to your head. There isn’t a helmet that is able to sustain such a direct impact or guarantee absolute protection to the rider on the market. Not even an Arai helmet.
The wearer of the helmet may be moving much faster than the drop speed of the impact tests. How come then, in the real world, do riders walk away from crashes at even much, much higher speeds? Arai have made this possible by minimising the impact energy that is directed into the helmet. This is achieved by letting the helmet slide over and allowing it to glance off objects.
Therefore, the impact energies the helmets outer shell needs to absorb may be dramatically reduced if the helmet can glance off obstacles and slide across uneven surfaces, thereby diverting impact energies. Arai use the smooth and round R75 shape as well as a unique construction system to make sure that this is what occurs if it happens to all go wrong.
To see the Arai range and book a fitting, with someone who knows what they are talking about, contact Megabikes on 01 478 4200. The range is large and covers a variety of budgets as well as styles.
