It depends. On a high level, polycarbonate is more expensive, flexible, softer, and lighter. Conversely, ABS is much cheaper, as well as harder, heavier, and more brittle. So if you want a helmet that’s thin and light, you’re much more likely to find that in a polycarbonate shell.

Boasting a higher tensile strength than polycarbonate, ABS contributes to the durability of helmets. Often used in skate-style helmets and budget-friendly options, ABS provides a hard, protective outer shell at a lower cost. However, ABS plastic is generally heavier than polycarbonate, making helmets less comfortable for long rides.

Polycarbonate has greater tensile strength, higher heat deflection temperature, and flexibility than ABS. ABS, on the other hand, has a higher natural UV (ultraviolet) resistance and rigidity compared to polycarbonate.

Compared to ABS, though, you’ll find that polycarbonate is thinner and lighter, so you’ll find it on higher-end helmets. It also has higher impact resistance than ABS. All of that, of course, means that these helmets are a bit more expensive than their ABS counterparts. You can find both bike and snow helmets that use polycarbonate.

Under the branch of thermoplastics lies two main types of plastic material: ABS and polycarbonate. ABS is a harder, heavier, more brittle but cheaper plastic. Example of ABS shell on Half Helmet. From Amazon.com Polycarbonate is more flexible, softer, lighter, and more expensive. Example of Polycarbonate shell on Half Helmet.