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Do electric vehicles need a specific tire for EVs? Know the 6 consequences for your car if you adopt these measures or not

Written by Paulo Nogueira
Published 25/12/2022 às 11:26
Updated 26/12/2022 às 10:30
Specific tire for electric vehicles is very important
Source: AES Technica

Despite all the technology involved in current electric vehicles, the tire is still the car's main point of contact with the road.

The promise of electric vehicles for low maintenance costs is a major selling point. With the exception of the tire, diesel particulate traps, oil change, spark plugs, exhaust and numerous other parts no longer need to be replaced on EVs (Electric Vehicle). Not even a muffler clamp gets in the way.

However, something unexpected happened on the way to the perfection of driving without gasoline. A tire's flexibility ensures that it will continue to serve as the car's final contact point with the road. Your air usage needs periodic replenishment. Furthermore, a silent engine has very specific traction, load and noise requirements. Tires designed for electric vehicles are mandatory.

When compared to conventional tires, how are EV tires unique? To find out what goes into the tire kiln and what the development tests showed before the tires hit the streets, several experts were consulted by the portal. Ars Technica.

You can install tires designed for regular ICE vehicles on your EV's wheels, although this is not recommended. EV tires are built to handle the unique weight, dynamic load and traction demands of EVs. Faster tire degradation, heat-related issues, and the possibility of wheel slip even with traction control can lead to a loss of directional stability if non-EV tires are used.

Weight and Load

Before any vehicle even starts moving, there are already noticeable differences between regular vehicles and EVs. Compared to vehicles with an internal combustion engine, electric vehicles tend to be heavier. The ICE S500 4Matic weighs just 4.610 pounds (2.091 kg), while the overall weight of the Mercedes-Benz EQS 450 4Matic electrified is 5.597 pounds (2.539 kg). Although they don't share a common chassis, all these automobiles belong to the same size category and market subset. Due to the need to use heavy batteries, the EV is approximately 1.000 pounds (454 kg) heavier. It's true that solutions to the weight problem are on the horizon, but for now, the tire's fundamental carcass design must be able to support the weight.

Many people believe that a tire's traction and grip can only be affected by the rubber compound or polymers it is made from. In addition to the compounds used, however, the tread pattern, the depth of the tread blocks and the void volume between them all have significant effects on a tire's stiffness and load capacity.

As far as static charge distribution is concerned, the battery's enormous weight is often distributed between the vehicle's front and rear axles. But there is always a cloud behind every ray of sunshine. The vehicle's dynamic mass would be improved if that weight were moved to a much smaller footprint at the center of the vehicle. If an electric vehicle is on the move and undergoes frequent changes of direction, a long, wide battery is no good. As the vehicle is in constant motion, the dynamic load capacity of the tire must be adequate. For an EQS weighing 5.597 pounds, that means structural rigidity not just at rest, but also during braking, cornering and acceleration.

Noise

Pirelli's Scorpion tire for crossovers and SUVs has EV-specific variants.

With no moving parts to create noise, electric vehicles are much quieter than internal combustion engines. Furthermore, there are no audible signs of a combustion engine, transmission, valve, exhaust or intake manifold, or even the slight ticking of high-pressure fuel injectors. Since the engine of an internal combustion automobile (ICE) muffles some of the noise produced by the tires, it is essential that the tires themselves are as quiet as possible.

Once an EV reaches typical suburban street speeds, the tires provide most of the sound radiating from the vehicle (both outside and inside), and this noise only increases when driving on highways.

Rob Williams, senior vice president of Hankook Tire, said that, to the nearest tenth of a decibel, powertrain noise accounts for approximately half of the total noise experienced by a combustion vehicle, while road noise accounts for the other half. . On the other hand, Hankook found that the electric motor contributes only 15% to the overall noise level of an EV, while road noise accounts for 40% and wind noise at high speeds contributes another 30%. Tire tread pattern is the main contributor to road noise at high speeds.

Active and passive noise cancellation has been used for years in combustion-powered vehicles, but there are now many more computer modeling tools to figure out the design of new, quieter tread patterns.

According to Ars, Ian Coke, director of technology at Pirelli North America, informed the publication that the company created its own software for this type of simulation. Before the advent of simulation software, it was discovered that by varying the longitudinal length (or slope) of the tread blocks around the circumference of the tire, and then alternating between large and small blocks from the inner shoulder to the outer shoulder, a significant amount tire noise could be cancelled. Now, with simulation and calculation tools, much more radically different ideas can be tested in a fraction of the time it would have taken 20 years ago.

traction under acceleration

It is in this area that one of the greatest difficulties in the development of an EV tire lies. Most electric motors generate massive torque more aggressively and instantly than most combustion engines, which causes the tire to take a greater shock than almost any ICE vehicle with a similar design brief. To take just one example, the Tesla Model Y has instantaneous acceleration unrivaled by almost any combustion vehicle in the same compact hatch/wagon/SUV market zone. This places a greater demand on the Model Y's tire performance envelope than anything else in its size class.

A vehicle's range is an important factor for many people, including automakers, tire manufacturers and consumers. Long tire life is already compromised to some extent if a tire provides great front-end traction, as softer rubber formulations are typically sacrificed to provide that bite on the road surface.

Tire service life

In 2022, Hankook introduced a winter tire for EVs.

It has been reported by many EV owners, even in the brief time they have been on the market, that the tires wear out much more quickly than those on combustion vehicles. And that's significant because tire replacement costs can add up quickly for EV owners. In an interview with Ars Technica, a respondent recently had to replace the tires on his Tesla Model S due to wear. He had only driven the car for 4.000 miles (6438 km). Tires fitted to electric vehicles require a more subtle approach to balancing durability and grip than their counterparts on internal combustion engine vehicles.

Autonomy

For optimal range, which is definitely the main concern of EV consumers, EVs need tires with less rolling resistance than an ICE vehicle. Electric vehicle manufacturers place a premium on energy-efficient tires due to their desire to maximize their product range. While low rolling resistance is nothing new, its importance for vehicles with an internal combustion engine is much less. According to Pirelli, a tire can affect the range of an electric vehicle by up to 40%, but only 15-20% on a vehicle with an internal combustion engine.

The tire of an electric vehicle is more resistant than that of a conventional vehicle with an internal combustion engine. Including the tread pattern, this is true. However, it is a delicate balancing act to strike the ideal compromise between low rolling resistance and grip.

Tire aerodynamic efficiency is also important but rarely discussed. Aerodynamic drag, which can be thought of as a type of rolling resistance, is transmitted across the front area of ​​the tire to the incoming air. A decrease in fuel economy and an overall shorter range are also consequences of wider tires.

Cost

There's no getting around the reality that EV tires are expensive and the problems with the international supply chain haven't helped. For the above reasons, tires for electric cars are more expensive than tires for vehicles with an internal combustion engine.

Finally, due to the above-mentioned factors, the market for EV-specific tires is much smaller than that for regular car tires; as a result, the field is narrower and there are fewer alternatives, leading to higher prices relative to non-EV tires. The good news for EV owners is that the industry as a whole is expanding, which should lead to a greater spread of knowledge and best practices regarding EV tires.

If you want to know everything about the world of VElectric vehicles, visit the CPG PORTAL AUTOMOTIVE BLOG HERE.

Paulo Nogueira

With a technical background, I worked in the offshore oil and gas market for a few years. Today, my team and I are dedicated to bringing information from the Brazilian energy sector and the world, always with credible and up-to-date sources.

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