What Are Circumferential Grooves?
Circumferential grooves in tires are channels that are molded around the circumference of a tire’s tread. These grooves run parallel to the tire’s rotation and are distinct from other types of grooves, such as lateral grooves, which cross over the tire’s circumferential grooves.
Circumferential grooves are the deepest grooves in a tire’s tread pattern. They remain visible and functional throughout the tire’s lifespan, regardless of wear. Generally, there are two or four circumferential grooves in tires.
What Is the Purpose of Circumferential Grooves In Tires?
Significance in Wet Conditions and Traction
One of the key functions of circumferential grooves is their role in maintaining traction, especially on wet surfaces, during rain, and in standing water. As a tire rotates, these grooves channel water away from the contact area between the tire and the road.
This action is crucial in preventing hydroplaning, where a layer of water builds up between the tire and the road surface, leading to a loss of traction. The design of these grooves is balanced, as a tire with large grooves (high void concept) offers excellent wet braking performance but can reduce the contact patch, affecting dry braking performance​​​​.
Impact on Tire Cooling and Cornering Traction
Circumferential grooves are not only important for water displacement but also play a role in the tire’s overall performance. These grooves add ‘side-bite’ to the tire, enhancing its grip during cornering, particularly on loose surfaces. Moreover, they contribute to cooling the tire, which is an important aspect of tire maintenance and longevity. This cooling effect is crucial for ensuring the tire performs optimally under various driving conditions.
Lateral vs Circumferential Grooves: The Difference
Lateral and circumferential grooves are two types of grooves in tire treads. They serve different purposes in tire performance and safety.
Lateral grooves run across the tire’s tread, perpendicular to the direction of travel. Their primary role is to improve traction by providing additional biting edges. This is particularly important for enhancing grip during acceleration and braking.
Lateral grooves also assist in water dispersion but do so across the width of the tire, aiding in preventing hydroplaning. But their anti-hydroplaning property is not as effective as the circumferential grooves.
Lateral grooves help in warming up the tire, which can be crucial for certain driving conditions, especially in racing or high-performance scenarios.
On the other side, circumferential grooves run parallel to the direction of travel, around the circumference of the tire. Their main function is to channel water away from the tire’s contact patch when driving on wet surfaces, thereby reducing the risk of hydroplaning and maintaining traction.