Why does a heat ring appear on a tire?

This blog will explain the cause of the heat ring on a tire and answer the following questions: what are the other types of tire wear patterns? When should you replace the tires? How to read the information on the tire sidewall?

Why does a heat ring appear on a tire?

A heat ring can appear on a tire when the vehicle is driven for a longer distance on an underinflated or flat tire. The heat ring appears on the sidewall as it is under too much stress from the weight and the driving force is acting on it. Hence, tires with heat rings must be inspected immediately. It is not recommended to drive the vehicle on the tire with a pronounced heat ring as it can cause a blowout and loss of control.

The inspection of the tire is performed by removing the wheel and separating the tire from the rim. Although the sidewall from the outside may look okay, there can be cuts or damage to the tire on the inside.

The wheel rim also gets damaged because the tire is not absorbing the vibrations of the road. If there is a tire pressure monitoring system in the car, then the sensor for the tire pressure monitor can also be damaged due to the underinflated tire.

Many premium cars are now equipped with Run-flat tires. The sidewalls of the run-flat tires are strengthened with additional wires so that when the tire is underinflated or flat, a vehicle can be driven for a limited distance and at restricted speeds.

The run-flat tires can be easily identified by checking the markings on the sidewall of the tire. On some tires Run flat will be written across the sidewall or ROF, EMT, and MOE are some of the common letters that mean the vehicle is equipped with Run-flat tires.

What are the other types of tire wear conditions?

The other types of tire wear conditions are explained below:

Tire wear on the outer tread.

This type of thread wear is caused when the tire pressure is less than the specified tire pressure. The specified tire pressure is written in the owner’s manual or behind the fuel filler cap. When the tire pressure is low, all the weight of the vehicle comes on the sidewall and outer treads.

Hence, the vehicle must be driven at the correct tire pressure. The affected tire can be replaced depending on the tread depth left on the outer sides. If there is no tire pressure monitoring system in the car then it is best to check the tire pressure once every month or use an aftermarket tire pressure monitoring system.

Tire wear on the inner tread

This type of tire wear occurs due to overinflation of the tire. If the tire pressure is more than the specified value, the contact patch of the tire becomes small as only the inner treads come in contact with the road.

The tire may need replacement depending on the tread depth left on the tire. It is also possible to correct the tire pressure and perform a tire rotation to even out the wear if the fault is noticed in the early stages.

Uneven wear or flat spots on the tires.

Flat spots occur on the tire when the wheel locks up under heavy braking. Uneven wear can also come if the driver has a habit of applying brakes immediately instead of a progressive application.

Uneven wear can cause a vibration when the vehicle is driven at high speeds. The entire contact patch can get a flat spot if the vehicle is stored for a long time. Therefore, placing the vehicle on jacks and removing the tires can help to prevent flat spots.

If there is too much uneven wear then tires must be replaced as it can also cause a loss of traction. In some cases, uneven wear is even caused due to worn-out suspension bushes. 

Sidewall bulge and cracks

A sidewall bulge is caused when there is a heavy impact on the tire. The side wall gets pinched between an object and the wheel rim. The wires on the tire bead get damaged and the air inside the tire enters the sidewall.

If the tire is not radial then the impact can separate the sidewall plies, allowing the air to enter the inner liner and creating a bulge on the sidewall. It is not possible to repair the sidewall and the tires with the bulge must be replaced.

The tire manufacturer can replace the damaged tire under the manufacturer’s warranty provided there is no damage on the wheel rim. Sidewall bulge can also occur if the tire bead is damaged during the installation of the new tire.

Tire chunking

This type of tire wear is common on sports utility vehicles. If the vehicle is regularly driven on a bad road surface or offroad, chunks of the tread can fall from the contact patch. Although tire chunking does not create a loss of grip the noise levels can significantly increase.

The grip can be affected if the vehicle is driven in rain or snow so if the damage on the tire tread is too much it is recommended to replace the tire.

When should you replace the tires? 

You should replace the tire every 3 to four years even if the vehicle has not covered many miles. Tires have different rubber compounds and the tire becomes hard as it ages. If the tire is not replaced then a crack starts to form on the treads and contact patch.

Ozone cracking is also common in hot countries. Due to prolonged exposure to sunlight and high temperature, the tire compound loses all its natural properties and develops cracks. There is no way to restore the tire compound and the tire has to be replaced.

If the vehicle is regularly used then one of the best methods to check the tire condition is a tread wear indicator. The tread wear indicator is present on the contact patch of the tire, when the tread reaches the level of the indicator, it is a good indicator that the tire is at the end of its service life.

A depth gauge can also be used to measure the tire tread depth, the depth is checked in three locations; outer, inner, and center. Overall reading should not deviate by 1 mm and the tire depth must be more than 2 mm. 


This blog explained the cause of the heat ring on the tire and also provided information on different types of tire conditions. If the vehicle is driven with tires that are in bad condition, it is very easy to lose traction at the drive wheels. The vehicle can also aquaplane and cause an accident in slippery conditions.