Why Tire Treads Have Grooves And What The Different Patterns Are For

There's a not-so-old song with a lyric that goes something like, "The tires are the things on the car that make contact with the road ..." While it makes for a catchy little chorus, it's not an entirely accurate sentiment, as it's largely just the tire's treads that are turning endlessly over on the concrete.

Singsong semantics aside, it's actually important that the tread is the part of the tire that connects with the surface of the road, as the grooves dug into the rubber provide drivers with vital safety functions. The primary purpose of a tire's grooves is to increase traction by bolstering friction between tread and concrete. Apart from that, the grooves are also designed to evenly distribute wear and tear on a tire to increase its lifespan, as well as reduce the amount of noise made as you drive, and they can even increase fuel efficiency by reducing rolling resistance. 

As the theory goes, the deeper the tire's tread, the more traction it creates with the road. That logic is particularly important when it comes to driving in adverse weather conditions, as deep grooves can help increase the flow of water away from a tire's raised surface area. This is important because even the smallest layer of water trapped between a tire and the road can increase the likelihood of the tire losing contact with the surface. That can, of course, lead to hydroplaning and, in turn, the loss of control over the vehicle.

If you've ever had to scour the market for a new set of tires from one of the major manufacturers, you no doubt noticed that the offerings in auto stores and big box outfits like Walmart — aka the exclusive home to Douglas Tires — all seem to have different variations in their tread patterns. However, there are, essentially, just three different types of tire tread available on consumer tires, including symmetrical, directional, and asymmetrical.

Though derived from the same basic design elements, the patterns can be arranged to produce different experiences on the road. A symmetrical tread pattern is the go-to pattern for tire makers, with the general look right there in the name. As both halves of the tire are identical, the symmetrical pattern is meant to provide a smooth, even driving experience, while increasing directional stability and reducing rolling resistance.

Directional tire tread, on the other hand, has the look of an arrowhead, with V-shaped grooves meeting in the middle of the tire. They are well-suited to driving in inclement weather, as the water, snow, and mud wicking design can dramatically reduce the risk of hydroplaning. Tires with directional tread are also good for hugging the road at high-speeds if you're a driver of the lead-footed variety.

Meanwhile, asymmetrical treads utilize different patterns on the inner and outer half of the tire, with one half handling water displacement and the other traction. These tires are commonly used on performance vehicles as they deliver excellent handling, curve stability, and solid protection against hydroplaning.