The material from which the shell is made is the outer hard shell of the helmet.
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Thermoplastic. Material used primarily in inexpensive motorcycle helmets; the most popular option in this category. Thermoplastic (most often it is polycarbonate) is notable for its low cost and has quite sufficient, although not very high, strength characteristics, but it is quite heavy, besides, it “ages” with use due to temperature changes and exposure to ultraviolet radiation; These helmets are recommended to be changed every 5 years.
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Thermoresin. In terms of basic properties, this material is similar to the plastic described above; at the same time, it is more durable and durable, however, it also costs a little more, which accordingly affects the price of helmets.
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Fibreglass (fibreglass). In this case, we are not talking about pure glass fibre, but about fibreglass — a composite consisting of fibreglass and a plastic base. Sufficiently strong and reliable, but at the same time quite heavy material, used mainly in mid-level helmets.
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Carbon. It is also carbon fibre — a composite material that combines carbon fibre and a polymer resin base. This combination allows you to achieve lightness and at the same time extremely high strength, but it is not cheap. Therefore, a carbon fibre shell is usually a si
...gn of a premium helmet.
— Fibreglass / Kevlar. The fibreglass described above, supplemented with a composite based on another fibre — Kevlar. Kevlar is not much inferior to carbon in terms of strength, while it costs less, and such material weighs noticeably less than fibreglass, which significantly affects the mass of the entire helmet. In this case, the materials are usually arranged in layers.
— Carbon / fibreglass. Helmets partly made of carbon, partly made of fibreglass; such a shell usually has a "puff" construction. About the features of each of these materials, see above, and their combination allows you to combine the advantages and partially compensate for the shortcomings. So, such combined helmets are cheaper than pure carbon ones, and in terms of strength they may not be inferior to them. However fibreglass is a heavy material, which accordingly affects the weight; however, such helmets still turn out to be quite light.
— Carbon / Kevlar. Helmets that combine carbon and Kevlar in construction — usually in the form of layers that make up the shell. Both of these materials are detailed above, and the combination is remarkable for its high strength and lower cost than pure carbon. At the same time, these helmets are still expensive, and weigh a little more than carbon ones.