Armour

Motorcycle armour describes the sections / pads (hard or soft) placed at exposed parts of the body including hips, knees, shoulders, elbows and spine designed to absorb some of the energy of an impact.

Motorcycle armour comes in different forms, from foam to more modern and expensive compounds capable of absorbing large amounts of energy.

Hard armor usually consists of a hard plastic backing with foam laminated to the inside. This type of armor is somewhat controversial because it is thought to not disperse force as well as the soft armor. It is also more likely to cause the leather immediately above it to wear through in the case of an accident.

The use of highly viscoelastic materials in motorcycle armor has allowed for elbow, knee, shoulder and back armor to be manufactured in a soft and pliable state at rest. Upon the introduction of shock the armor changes at the molecular level and adopts extremely rigid and protective properties. Examples of this armor are SAS-TEC, d3o, Rukka APS air, EXO-TEC and TF armor. They are currently being used in pinnacle jackets, pants and suits by manufacturers such as REV'IT!, Firstgear, BMW Apparel, Scorpion, Rukka and Aerostich respectively.

Whilst such systems have been shown to achieve similar performance to traditional foam and hard armor solutions, perceived benefits of molecular armor systems above more established types are pliability and comfort.

In Europe there are two standards covering "motorcyclists' protective clothing against mechanical impact" - EN 1621-1:1997[1] and EN 1621-2:2003[2]. Both standards assess the performance of protective devices by measuring the force transmitted through it when impacted by a falling mass.

EN 1621-1:1997 assesses devices that are designed to protect the shoulder, elbow and forearm, hip, knee and lower leg regions. The test apparatus consists of a mass of 5kg with a 40mm x 30mm striking face, dropped onto the sample mounted on top of a 50mm radius hemispherical dome. The anvil is further mounted onto a load cell, allowing a measurement to be made of the force transmitted through the protector. The kinetic energy of the falling mass at impact is required to be 50J.

A protector subjected to this test method is deemed to conform to this standard if the average transmitted force of nine tests is less than 35 kN, with no single test result exceeding 50 kN.

European Standard EN 1621-2:2003[2] defines two levels of performance for CE approved back protectors. The test apparatus and procedure is similar to that of EN 1621-1:1997[1], but with a different impactor and anvil configuration. The impactor is a rounded triangular faced prism, of length 160mm, base 50mm, height 30.8mm and radius 12.5mm. The anvil is a radiused cylinder, with its axis orientated to the direction of impact, of height 190mm, diameter 100mm and rounded end radius 150mm. When tested to the procedure defined in the standard, the two levels of performance are:

"Level 1 protectors: The average peak force recorded below the anvil in the tests shall be below 18 kN, and no single value shall exceed 24 kN.

Level 2 protectors: The average peak force recorded below the anvil in the tests shall be below 9 kN, and no single value shall exceed 12 kN."

There is however, no mention of hyperextension/hyperflexion restraint (aka whiplash, but can include the whole spine), or of torsional restraint (torsional injuries can result from the afore-mentioned blows to hips or shoulders). This is the area where designs featuring hard armor could potentially be better than the softer types. One potential cause of injury that should be born in mind is the contents of any bag or rucksack worn by the rider. Back protectors are often not included in the standard complement of armor although many jackets allow a back protector to be installed. Because of the more delicate nature of the spinal column, back protectors require that lower levels of force be transmitted. However, in the Cambridge Standard for Motorcyclists Clothing, Roderick Woods asserts that the majority of spinal injuries are caused by blows to the hip and shoulders. In the rare circumstance that a motorcyclist received a direct blow to the back the damage would be unmitigatable by armor. The concept of a "back protector" is therefore not endorsed by Woods.