Tire Design part 1 Basic Tread Design

The contact points between the road and you car consist of four small patches of rubber. The tire too many drivers is probably one of the last things they worry about when driving down the road, that's until one of them goes flat.

Some of you have wondered, others not, why tires have different patterns on the bottom of them. Is there significance in the intricate design molded into them or is it just for looks? A few of you also might not have a clue what I'm talking about.

I could probably argue the reasoning was because of looks, but in reality, some major science goes into those designs. In this post, I'm going to cover the basic design pattern of the tire. In the future posts I'm going to go a little more in depth on how these designs effect performance on dry, wet, and icy pavement along with gravel and dirt.

Symmetric Tread Design
Symmetric tread design is exactly what it sounds like; the design is symmetrical across the center of the tire so that the inboard and the outboard tread patterns are the same. The main benefit to symmetrical treads is multiple tire rotation patterns can be used.

Asymmetric Tread Design
An asymmetric design is used for a mixture of surfaces (dry, wet, and icy). In these tires, the tread design changes across the bottom of the tire. For example, an asymmetrical tire would have smaller pieces of tread by the inboard side of the tire to deal with icy or wet roads. While wider pieces of tread are located on outboard side of the tire for grip on dry roads. These tires also allow for multiple rotation patterns like the symmetrical thread designs.

From tirerack.com

Directional (Unidirectional) Tread Design
They're known as directional tires because they can only rotate in one direction otherwise they don't work properly. Directional are best known for their ability to move water out of the way by single or multiple V-groove(s) located on the bottom of the tire. This helps the tire become more effective at fighting hydroplaning on water at speed. The rotational pattern is limited compared to the symmetric and asymmetric because this type of tire can only be rotated from the front to the back of the car.

Asymmetric and Directional Tread Design
These tires are very similar to directional except that the V-groove(s) is/are offset from the center of the tire. Rotational pattern is same as the directional.

-DK