Why Do Tires Have Grooves: Reason & Importance

Whenever you see a tire, you will see grooves or tread patterns in it. The grooves have become part and parcel of the tires, and almost everyone takes them for granted. As it is a common element of automobile tires, we don’t focus on it.

Thus, most people don’t know why do tires have grooves? Also, many people fail to differentiate between the grooves and tread of the tires. In fact, most people think that the tread in the tire is itself the groove.

But that’s not the reality. The grooves are inside the tread of the tire, not the tread pattern. Also, its main benefit includes the increased traction between the tire and the road for safer riding. However, this is only a superficial discussion. So, let’s jump deep into it.

Why Do Tires Have Grooves

What Is Grooves?

When you see the tires of an automobile, you will immediately notice its treads. The treads actually refer to the smaller patterns you see in the rubber construction of the tire. Most people consider these smaller patterns as grooves of the tire.

But that’s not the reality.

So, we first need to know, “What is tread on a tire?”

The tread on a tire refers to the rubberized construction right around its circumference. It makes contact with the ground you are driving the vehicle. But that’s not the groove.

The groove refers to the long and parallel running lines through the patterns or tire treads. A tire mainly has three to four grooves running inside the patterns or treads. You will also see multiple smaller grooves in one tread of the tires. The tire’s tread and groove help the car stay stable on the roads for safe riding.

However, you need to be aware of one point-

The tire tread and grooves are only seen in regular cars. Sports cars or racing cars don’t have grooves and treads since their main purpose is to get the maximum speed, and so, the tires need to lessen friction with the roads. That’s why the tires of racing cars are mostly flattened without ant patterns, and so, they get better speed and acceleration. Read: Remove Road Paint from Tires – 4 Effective Ways

Types of Grooves in Cars:

Depending on the location and direction of the grooves, you will mainly see two types of grooves on tires for every car, except the racing automobiles. It will help you understand the tire grooving secrets better.

The list includes:

1) Circumferential:

These are the larger and longer grooves you will find within the car’s tire tread pattern. They run parallel and all around the tire. Usually, a tire will have three to four circumferential grooves that depend on the tire’s width.


The circumferential grooves of the tire of a car include the major portion of a tire’s void ratio. The void ratio of a car refers to the distinction between the contact area and groove area.

Let’s make it simple –

The contact area is the portion of the tire that comes in contact with the ground. And the groove area has space and doesn’t come in contact with the ground or road. The ratio between these two parts of a tire is referred to as the void area, and the majority of it is made up of circumferential groove parts of the tire.

The purpose of the circumferential groove is to contribute to the wet traction of the tire. It allows the water to flow quickly and easily through the tread design and keeps the tire dry.

Thus, it links and directly controls the hydroplane resistance of the car. It comes in handy while driving through the standing water on roads to keep the car stable and safe.

Read: Powder Coat VS Paint Wheels: Which one is best?

On top of it, the circumferential groove of the car tires comes with lateral biting edge properties. Driving the car through a loose surface increases the traction around the corner and edges of the tire and ensures a safe driving facility.

The best benefit of the circumferential grooves is that they remain visible and functional throughout the lifespan of the molded rubber tires. It is made possible due to the deepest groove construction of these elements of the tire.

2) Lateral:

While the circumferential grooves are usually molded directly around the tires, the lateral grooves are molded across the entire tire in smaller parts. They are less deeper than the circumferential grooves and aren’t visible throughout the entire lifespan of the tires.

Lateral type

Likewise, the circumferential grooves of the tire, lateral grooves also contribute to the overall void ratio of your car’s tire. Thus, it also increases the biting edge of the car tires and helps in wet traction for a safer riding experience.

You will see that the lateral grooves of the tire intersect the circumferential grooves on both sides. These grooves are between the outboard and inboard tread patterns of the car. Thus, it also contributes to the independent design and development of tread blocks for better traction.

However, on either side of the tires, some lateral grooves will reach only one side of the circumferential grooves. These grooves are referred to as lateral notch.

The depth of the lateral groove is generally less than 2/32-inch, and it improves the car’s overall stability. So, the lateral grooves disappear rather too soon.

Why Do Tires Have Grooves?

We have already mentioned the applications of the grooves on the car. You have seen that both the lateral and circumferential grooves of the vehicle contribute to its void ratio. Thus, it controls the part of the tire that will come in contact with the driving ground.

So, what is the reason? Is it only for controlling the car’s void ratio?

Tire tread groove patterns

Well, the main use of grooves is in their improved traction. Tires with a higher number of deeper grooves ensure excellent traction on the roads. So, you will enjoy better stability and grip while driving the vehicle. Therefore, it ensures a safe riding experience.

Also, when you drive on wet roads and standing water, the circumferential grooves allow the water to flow through it and not get stagnant. So, the tires of the car won’t slip even in wet conditions. It means you will enjoy a safer and smoother riding experience with better grooves on the tires.

That’s why people need to change the tires when the grooves start disappearing from the tires, causing a loose grip on the tires.

However, the grooves on the tire have one big disadvantage as well. It enhance traction, and the tire tread pattern boosts friction. These two properties, therefore, together, contribute to the reduced speed of the car. Hence, you will never see grooves and treads on the racing cars as speed is key.

What Does Grooved Pavement Mean?

If you have a motorcycle or car, the grooved pavement sign meaning is increasingly important for you. The Grooved Pavement Sign or W8-15 warns the drivers that there is a grooved pavement right in front of them.

Pavement Sign

On highways and roads, sometimes there is a grooved pavement portion. So, this part of the street is textured instead of being smooth. Thus, drives might find jerking and loss of control while driving on the grooved pavement. So, the W8-15 sign is used to alert the drivers about the front lying texture pavement of the roads for a safe and smooth driving experience.

This warning is crucial since the car wobbles on grooved pavement, especially at higher speed, and might cause minor injuries to the driver and passengers. When the driver gets the early signal of the grooved pavement, he can slow down the car speed and avoid the car wobbling. Read More: Rims Vs Hubcaps: Differences & Which is Better

Does Grooved Pavement Damage Tires?

Well, this is a critical question that many car and motorcycle owners ask. They are concerned that driving their vehicles for a long time on grooved pavement might damage the tires and reduce their lifespan considerably.

You need to understand that grooved pavements are not permanent construction. Road constructors use the grooved pavements to help the asphalt surface dry quickly and will soon resurface the roads and highways to remove the grooved pavements. Thus, the wear and tear caused by these textured portions to your tires are pretty negligible.

Also, grooved pavement motorcycle roads don’t affect the lifespan of the tires as significantly as most riders think. So, you shouldn’t worry about it. Instead, it is better to focus on your safe riding skills and avoid wobbling on the textured ground.

You may also read: Overinflated Tire By 5 Psi: Recommended Tire Pressure [Guide]

Final Words:

The groove is used to improve the traction and grip of the tires on the roads. Also, it helps in removing the water while driving on wet roads and streets. Thus, the grooves and treads of the tires are purely for safety purposes. These features also improve the riding smoothness of the car and motorcycle.

As you drive the vehicle for a longer period, the grooves start wearing out slowly. You should replace the tires when the grooves inside the tread pattern of your vehicles disappear. It ensures safe riding in all conditions.

Also, you might choose a tire with fewer grooves and treads to improve the acceleration and drive speed of the car.

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