Kevlar is a heat-resistant and very strong synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, this high-strength material was first used commercially in the early 1970s as a replacement for steel in racing tyres.
Kevlar is used in tyres in two ways:
- As a replacement for the steel coils that form the tyre’s edges (known as beads);
- As sub-tread, which is a protective layer that rests between the external rubber and the internal fabric casing that forms the tyre’s structure.
How strong is Kevlar?
The specific tensile strength (stretching or pulling strength) of both Kevlar 29 and Kevlar 49 is over eight times greater than that of steel wire. Unlike most plastics it does not melt: it’s reasonably good at withstanding temperatures and decomposes only at about 450°C (850°F). It is strong relative to its weight.
Can Kevlar stop a bullet?
Kevlar is able to stop a bullet due to its molecular structure that is why it is also used to construct bulletproof vests: it’s lightweight, durable, flexible, and most importantly, extremely difficult to break through. Does that mean your tyres are bulletproof? The specific structure used in manufacture of bulletproof vests in not applicable to tyres, so no, but it does mean they’re substantially stronger and could reduce the damage to a tyre in the event of a bullet impact.
The following are popular tyres build with Kevlar.