The Critical Role of Tires in Electric Vehicles: Why BEVs Need Specialized Tire Technology

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The Weight Challenge: Heavier Vehicles Require Stiffer Tires

BEVs are heavy, and it’s easy to understand why. For instance, to achieve a 400-kilometer range, an internal combustion engine vehicle (ICEV) might need about 30 kilograms of fuel, while a BEV could require around 450 kilograms of battery. Even though electric motors are lighter than combustion engines, the overall vehicle weight for BEVs tends to be about 20-30% higher. This added weight puts a lot of stress on the tires, yet you still want to keep them as narrow as possible for aerodynamic efficiency.

Various tests have shown that the same tire used on a lighter ICE vehicle versus a heavier BEV will wear about 20% faster on the BEV. To address this, you need to increase the stiffness of the tire. Some BEV-specific tires, for example, offer 25% higher lateral stiffness and 20% higher cornering stiffness compared to standard SUV touring tires. When you turn the vehicle, the heavy weight of the BEV resists this motion, which can stretch the tire laterally. By altering the tire's profile and enhancing the sidewall's rigidity, you can improve lateral stiffness, thus improving steering response by reducing the sloppiness that might occur when you turn.

Furthermore, more weight typically leads to faster wear. Therefore, BEV tires often use a stiffer compound to minimize the wear caused by the vehicle's higher weight. A key observation from experience is that BEV-specific tires usually have a flatter contact patch for a given width, which means more rubber touches the road. This design helps distribute the load more evenly, reducing wear.

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Efficiency Matters: The Critical Role of Rolling Resistance

Efficiency is crucial for BEVs. Electric vehicles are extremely efficient, meaning that even small changes can have a significant impact on range, especially when it comes to wheels and tires. For tires, the focus is on rolling resistance—the energy lost as heat as the tire deforms while rolling. To measure tire performance in this regard, we use the coefficient of rolling resistance.

Let's illustrate this with a simple example. Imagine an 1800-kilogram vehicle traveling 350 kilometers. If you compare two tires—one with a rolling resistance coefficient of 0.01 (a typical car tire) and another with 0.005 (an excellent car tire)—you can see a significant difference. The tire with higher rolling resistance could cause the vehicle to use an additional 8 kilowatt-hours of energy over that distance.

Now, consider the difference between an ICE vehicle and a BEV in this scenario. For the ICE vehicle, this would translate into needing about 4.0 liters of extra fuel to compensate for the tire's higher rolling resistance. For a BEV, however, it would mean an additional 8 kilowatt-hours of battery power. Adding 8 kilowatt-hours to a BEV's battery is significant—it could easily represent a 10-15% increase in battery size, which means higher costs, more weight (around 50 kilograms), and the need for additional space. This simple tire choice could either reduce or extend your range by up to 50 kilometers.

For BEVs, tires play a major role in determining range, whereas, in an ICE vehicle with a large fuel tank, you might not even notice the difference.

Fleet Operations and Sustainability: The Bigger Picture

In corporate fleets, the impact of a 10-15% reduction in efficiency due to tire selection can be significant. For BEVs, this reduction in range per charge directly affects work efficiency and can become a serious concern for drivers who worry about range. In countries like Norway and France, where the Electricity Emission Factor is low, the impact on CO2e emissions might be minimal. However, in countries like Australia, where the factor is high, the impact is far from negligible.

Historically, tire negotiations in car lease contracts have focused on price, with little consideration for the specific needs of BEVs. Moreover, few leasing companies are equipped to address these concerns. However, from the perspectives of sustainability and safety, it might be necessary to start including specific tire requirements for BEVs in these discussions.

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Conclusion

Tires are more than just rubber on the road, especially for electric vehicles. The increased weight, need for efficiency, and high torque of BEVs require tires specifically designed to handle these challenges. Whether you're a fleet manager or an individual EV owner, understanding the importance of tire selection can lead to better vehicle performance, longer tire life, and greater sustainability. As the automotive industry continues to evolve, so too must our approach to the components that keep our vehicles moving efficiently and safely.

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