Every now and then I will get a question from a customer asking about a tire’s tread design that does not “look right.” According to the customer, the tread design on the driver side and passenger side tires are not pointing in the same direction. This is a good time to discuss the variety of,tread patterns used by tire manufacturers.
Symmetric Tread Patterns
A symmetric tread pattern is the most common design. It features continuous ribs or independent tread blocks across the tire’s entire tread face where both inboard and outboard halves feature the same pattern. Tires featuring symmetric tread patterns allow the use of multiple tire rotation patterns.
Continental ContiProContact Michelin Pilot HX MXM4
Asymmetric Tread Patterns
An asymmetric pattern is often confused with a directional tread pattern and is the source of the confusion that I mentioned earlier. This pattern changes across the face of the tire to blend the requirements of dry grip, water dispersal and snow traction.
By incorporates larger tread ribs/blocks on the outboard side of the tire, corninering stability is increased on dry roads by offering a greater contact area.
The inboard side of asymmetric designed tires usually features smaller, independent tread blocks to aid wet and/or winter traction when driving straight ahead.
Tires featuring asymmetric tread patterns allow for rotation to either side of the vehicle and are identified with mounting instructions printed on the side wall designating "Mount this side out."
Kumho Ecsta ASX Continental ExtremeContact DWS
Directional (Unidirectional) Tread Patterns
A directional tread pattern is designed to roll in only one direction. It incorporates lateral grooves on both sides of the tire’s centerline that point in the same direction and result in v-shaped tread blocks. These grooves enhance hydroplaning resistance at high speeds by pumping water more efficiently through the tread pattern. Directional tires are to be used on one side of the vehicle and are intended to be rotated from the front axle to the rear axle. If different tire sizes are used on the front and rear axles, the tires become location-specific and tire rotation is not possible unless the tires are remounted.
Michelin Pilot Sport A/S Plus Bridgestone RE960AS