For many years, motorcycle helmets were primarily made from two types of materials: molded-injected hard plastic and fiberglass. However, helmet technology has advanced just like the technology in everything else. You can now find helmets made from more exotic materials like carbon fiber and Kevlar.
But there is nothing wrong with traditional plastic and fiberglass helmets and each has its advantages. The important thing is to find the best combination of comfort, weight, protection and cost for the type of riding you do.
Plastic helmets are still the most common. They use a specially designed plastic that stands up well to strong impacts, particularly the kind associated with motorcycle accidents. They are designed to offer a good balance between strength and weight. These helmets have a thick layer of foam padding under the plastic that is designed to collapse on impact and therefore absorb some of the force that would otherwise be received by the head. They are also usually the least expensive helmets to buy.
Fiberglass motorcycle helmets offer an excellent combination of toughness and flexibility and are becoming increasingly popular with all types of riders. The outer shells are constructed of laminated fiberglass and are designed to absorb as much blunt force trauma as possible from an impact. They are more likely to experience breakage and cracks than plastic, but this “brittleness” is what gives it a “shock-absorbing” effect and therefore less chance of serious injury. While fiberglass helmets tend to be more expensive than plastic helmets, they are also much lighter and more comfortable to wear, especially on long or hot rides.
Carbon fiber helmets are relatively new and are mainly used in racing helmets, where extreme protection, extreme lightness and consequently high cost are justified. Carbon fibers are produced by overheating acrylic fiber to greatly increase its stiffness and strength, while remaining very light. This type of compound can produce the strength of metal in a very lightweight unit. These are the hallmarks of a high-quality, value-priced bike helmet.
Kevlar, on the other hand, is produced by taking a polymer, dissolving it in a solvent, and using the resulting extracted fibers to spin yarn. By itself, Kevlar does not have the protective strength of carbon fiber. But when combined with carbon fiber to produce a laminate, the result is a material that is three times stronger than Kevlar alone. This is really the best of both worlds, but it also results in a very expensive helmet that is, for the most part, only justified for professional racers.
Regardless of the material, cost, look, weight, or quality of helmet you choose, keep in mind that wearing any motorcycle helmet is better than going without one. Find one that is within your budget and is comfortable for you. Consider it an excellent investment that can literally save your life.