Tire treads are more than just whatever pattern caught the manufacturer’s eye. The designs are essential to grip and handling, and in the case of directional tires, how they’re mounted on the car.
Also known as uni-directionals, these tires are constructed and their treads are designed to rotate in only one direction. They’re well-suited for high-performance handling, but have special requirements for mounting and rotation.
If you look at a directional tire head-on, you’ll see that the grooves form a V-shaped pattern in the tread. Directional tires are usually wide and have bigger tread blocks to improve stability – good for dry pavement, but more likely to trap water under them when the roads are wet. That's where the V-shaped grooves come in: channeling water away, providing better traction and reducing hydroplaning.
Another tip-off is on the sidewall: there will be an arrow indicated the direction of rotation, or a warning that one side must be mounted facing out. This indicates how the tire should be mounted on your rims to ensure that the tread pattern is in its optimal position. Directional tires often include special compounds on the edges to reduce shoulder wear, so mounting them properly will help ensure longer tire life.
Generally, a directional tire will provide better handling, stopping power and heat dispersal than a multi-directional tire. The trade-off is that since the design is primarily used for performance tires, they will be more expensive, with a stickier compound that makes for a better drive but will wear faster than a conventional tire.
Be sure that the installer mounts them with the arrow facing outward and in the correct direction. Running them “backwards” will reduce their performance and can wear the pattern irregularly. Don’t mix tires: all four should be directionals for optimal handling.
Rotating your tires adds to their life expectancy by evening out everyday wear. It’s usually done by switching the wheels and tires diagonally or from side to side, changing the tread area that gets the most amount of wear.
Directional tires have to be treated differently. Because they’re meant to turn only one way, directionals can only be rotated from front to back, remaining on the same side of the vehicle. Even that might not be possible, because many performance vehicles have differently-sized wheels front-to-back.
Aside from their specific rotation needs, directional tires need the same type of care and concern as all other tires. Their pressure should checked monthly, even if the vehicle has a tire pressure monitoring system – the tire can be low enough on air to affect fuel consumption and handling, but not enough to trigger a warning. The sidewalls should be examined regularly for cracks or bulges, and the depth of the tread measured periodically, especially on a performance tire. Finally, if they’re summer or all-season tires, they should be swapped for winter-specific rubber when the weather gets cold.
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