Dec 28, 2022 07:00:00

Why should electric cars have special tires?

Electric vehicles, which are said to be environmentally friendly because they do not use fossil fuels for driving, are recommended to use 'electric vehicle tires' that are different from gasoline vehicles. Ars Technica, a technology media, summarizes the question, 'Why do electric vehicles require special tires?'

Here's why electric vehicles need EV-specific tires | Ars Technica

https://arstechnica.com/cars/2022/12/heres-why-electric-vehicles-need-ev-specific-tires/

Electric vehicles and gasoline vehicles are similar in appearance, but there is a big difference in their internal structure. As a result, running an electric car on the same tires as a normal gasoline car risks accelerating tire wear, increasing heat-related problems, and losing directional stability. Ars Technica explains why electric vehicles should use special tires as follows.

·weight
One of the major differences between gasoline and electric vehicles is the difference in vehicle weight. Because electric cars have larger batteries, they tend to be heavier than gasoline cars of the same size. For example, the weight of the Mercedes-Benz electric car 'EQS 450 4MATIC' is 2539 kg, but the weight of the gasoline car 'S500 4Matic' of almost the same size is 2091 kg, which is a difference of about 450 kg. Therefore, it is said that the load index required for the tires of electric vehicles is larger than that of gasoline vehicles.

The weight a tire can withstand is influenced not only by the composition of the raw materials used, but also by the pattern and depth of the grooves. Also, whether the heavy battery is evenly distributed throughout the vehicle or centrally located to reduce dynamic loads while driving will affect the required load index of the tire.

·noise
Electric vehicles without an internal combustion engine are said to produce significantly less noise than gasoline vehicles. However, it has been pointed out that the noise from the wind and road surface, which was drowned out by the engine noise in gasoline vehicles, is more audible in electric vehicles with quiet motors.

According to Rob Williams, senior vice president of high-performance tire maker Hankook Tire, drive engine noise accounts for about 50% of noise in gasoline vehicles, while road noise accounts for about 30%. . On the other hand, in electric vehicles, motor noise accounts for about 15%, road noise accounts for about 40%, and wind noise due to high-speed driving accounts for about 30%. Tire manufacturers are researching and developing tire

tread patterns that can reduce noise as much as possible in order to reduce road surface noise caused by high-speed driving.

・Traction during acceleration
One of the major reasons why gasoline and electric vehicles require different tires is the difference in traction (driving force) between the tires and the road surface. Most electric motors produce more torque instantaneously than combustion engines, resulting in more impact on the tires. However, tires that emphasize traction tend to sacrifice durability and have the disadvantage of shortening the life of the tire.

・ Tire life
Even at the time of writing the article, which has not been so many years since the spread of electric vehicles, some owners have pointed out that 'the tire life is shorter than that of gasoline vehicles.' Driving with gasoline tires shortens the life of the tires and requires frequent replacement. A friend of Ars Technica writer Jim Resnick said he was forced to change tires after only 4000 miles (about 6400 km) on Tesla Model S.

·Cruising distance
The effect of

rolling resistance , which acts in the direction opposite to the direction of travel of the tires, on cruising distance is said to be about 15-20% for gasoline vehicles, but it is said to be considerably larger at 20-40% for electric vehicles. Choosing the right tire that balances rolling resistance and grip on the road is key to extending the range of an electric vehicle.

Unfortunately, at the time of writing the article, tires for electric vehicles are more expensive than those for gasoline vehicles. However, this is due to the size of the market and the number of players involved, so as electric vehicles become more common and the market grows, so will the price of electric vehicle tires, Resnick concludes. .