SNELL stickers cost much more on Motorcycle Helmet

As mentioned, during the helmet absorption test, helmets are dropped, using gravity to accelerate the helmet to a given speed before it smashes onto a test anvil bolted to the floor. By varying the drop height and the weight of the magnesium headform inside the helmet, the energy level of the test can be easily varied and precisely repeated. As the helmet/headform falls it is guided by either a steel track or a pair of steel cables. That guiding system adds friction to slow the fall slightly, so the test technician corrects for this by raising the initial drop height accordingly.

The headform has an accelerometer inside that precisely records the force the headform receives, showing how many Gs the headform took as it stopped and for how long.

If you test a bunch of helmets under the same conditions, you can get a good idea of how well each one absorbs a particular hit. And it's important to understand that as in lap times, golf scores and marriages, a lower number is always better when we're talking about your head receiving extreme G forces.

The hardest Snell test for a motorcycle helmet is a two-strike test onto a hemispherical chunk of stainless steel about the size of an orange. The first hit is at an energy of 150 joules, which translates to dropping a 5-kilo weight about 10 feet—an extremely high-energy impact. The next hit, on the same spot, is set at 110 joules, or about an 8-foot drop. To pass, the helmet is not allowed to transmit more than 300 Gs to the headform in either hit.

Tough tests such as this have driven helmet development over the years. But do they have any practical application on the street, where a hit as hard as the hardest single Snell impact may only happen in 1 percent of actual accidents? And where an impact as severe as the two-drop hemi test happens just short of never?

The Snell sticker has become a marketing gimmick. A manufacturer puts that sticker in his helmet and he can increase the price by $50 to 100. Because the image associated with Snell means a better and stronger helmet. Therefore must be worth a whole lot more money.