Have you ever looked at a tire sidewall and noticed an arrow? Or looked at the tread pattern of a tire and noticed a distinct V or Y contour to the center of the tread? If so, those are directional tires.
Some tires have a symmetric pattern of ribs and grooves, very uniform in shape across the surface of the tread. Others have an asymmetric pattern, where the inboard and outboard parts of the tread are distinctly different in their design. Directional tires are designed with their lateral grooves pointing “downward,” almost like two waterfalls that meet in the middle.
Why are directional tires designed that way?
In a perfect world for tires, it’d never rain, pavement would be smooth and dry all the time and we could all drive on racing slicks. That, of course, isn’t the case and one of the main jobs of any tire is to provide good wet-weather traction.
Directional tires do a much better job of channeling standing water away from the tire’s contact patch, giving them enhanced performance in wet weather. The design of the voids in a directional tire means that as well as routing water backward behind the contact patch, it also spreads it outward toward the edges of the tire. The directional design also means an improvement in stability and road manners at high speeds, making them a great choice for high-performance cars.
Directional tires are also inherently more efficient when they rotate in one direction. Especially when they’re made using a low-rolling-resistance tread formulation, directional tires can mean a jump in fuel economy. Plus, if the aesthetics of tires are important to you, there’s a definite cool-factor to the appearance of directional tires.
Pros and cons of directional tires
We’ve already listed the main advantages of directional tires — better stability, fuel economy and wet-weather performance — but they have one major disadvantage as well.
You no doubt know that you need to rotate your tires front-to-rear at regular intervals, in order to ensure even wear. Some tires require a simple front-to-back rotation, while others require an X-shaped cross-rotation. Directional tires can’t easily be rotated in an X pattern without going through the trouble of dismounting the tires from the rims, flipping them around so the proper sidewall is facing outward, then remounting the tires before cross-rotating them.
As a result, most people will just do a simple front-to-rear rotation when it’s time to rotate their directional tires. Mounting directional tires so that the pattern is facing in the wrong direction will negate any of the advantages in terms of wet-weather traction and high-speed stability — in other words, it defeats the purpose they were designed for.