Quote:
Nylon makes a wonderful reinforcing fiber for tires, but Kevlar does not.
Kevlar tends to shatter like glass when compressed. That means the tire has to be handled carefully and more importantly, the tire can not be allowed to run underinflated!!!
Where on earth did you acquire this misinformation?
"Fiber B," a nonwoven aramid material, was developed by Goodyear and DuPont specifically to be both a carcass and belting material for tires. DuPont applied the trademark Kevlar to it, and Goodyear had its own trademark (Flexten?).
Technically, the material was a success, and several automobile tires were made with it and marketed to the general public, who could care less. It was a marketing disaster because it lacked the sex appeal of "steel-belted," which sounded ever so macho.
Aramid/Kevlar is very resistant to stretching, so in a savvy marketing repositioning, Dupont devised sandwich composites that redirected direct impacts on a Kevlar surface to stretching vectors, and marketed the Kevlar sandwiches as a way to make "bulletproof" vests. Meanwhile, Kevlar made great inroads toward its original intended purpose, as a tire fabric, not in automotive tires, though, but in high end bicycle tires, which must be very light in weight and strong.
As an automobile tire component, aramid (Kevlar) remains a highly desirable material. However, it is a bit harder to work with than some alternatives, partially because of the very qualities that make it desirable, and it is also more expensive than some alternatives. Without a strong marketing hook, then, which it continues to lack, Kevlar and other aramid materials continue to be rarities in commercial tires. More's the pity.