How are Kevlar tires different from other tires?

Question

I bought a truck recently and it came with tires made (partially) with Kevlar.

What advantages do Kevlar automotive tires have over tires made with more traditional materials?

Reading through DuPont's page on the topic is not very enlightening: it has a lot of fancy, vacuous words that do not give much in the way of practical information.

I read a review of a Goodyear tire with Kevlar but it talks about the tire as a whole, which includes some other aspects which set that tire apart. It does not give a clear indication of how the Kevlar sets the tire apart from other similar tires.

Given two tires, one reinforced with Kevlar and another that is not, what tradeoffs would there be between the two tires? How are they different? Why would I, as a driver, choose to put one or the other type of tire on my vehicle?

Answer 1

Since what it does it pretty well close held, I'll have to take a stab at this in the dark, but I think it's an educated guess.

I think there are two things which set it apart: weight & toughness

First, most radial tires use steel for the belts. The belts are interwoven steel threads which are about as wide as the tread of the tire. This makes the tire stand up to many of the hazards which we find on the road, like rocks or potholes. Steel, as we know, is pretty heavy. Kevlar, on the other hand, is much lighter than steel. Kevlar can also replace the steel cord which is used in the bead where the tire mates to the rim. It is just as strong as steel (if not more so) at a fraction of the weight.

Secondly is the toughness. Kevlar has more resiliency than does steel. Steel strands can over time start breaking if stressed enough. Kevlar, on the other hand, will stand up to flexing with out self destruction until it starts to wear due to exposure. Inside the rubber it is completely encapsulated, which makes it fairly impervious to any type of stress fracture. While it should be noted most steel belted tires will not suffer this fate, either, it could happen a lot easier with steel than with Kevlar.

Answer 2

I have been in the tire industry for over 20 years and have had to study the internals of tire design and function.

Paulster2 is mostly correct, however Kevlar was not initially made by DuPont to replace steel cords but rather as a contractual agreement with the DOD for replacement body armor.

The Kevlar is used in the sidewalls of tire only (where steel cords are not practical to use) not in the tread itself to allow for better off-road reliability. The steel packs in a tire are located only in the repairable area of the tire (BFGoodrich are an exception to the rule in the KO, KO2 and KA series tires, the steel cords fold over about an inch onto the sidewall and end just before the sidewall tread ends).