Treading a new path
The rapid growth of the electric vehicle (EV) market means that automotive manufacturers across the entire supply chain are having to re-think their R&D approach to reflect this new normal. Tyre technology is a prime example of this scenario, with traditional suppliers having to deliver new innovations that will enable their products to be successfully deployed on EVs
And as Jaap Leendertse, general manager PCR/SUV tyre development at Sumitomo Rubber Europe observes, the successful players here will be the companies that recognise the importance of offering customers products that are purpose-designed for EVs. “Battery electric vehicle (BEV) and plug-in hybrid electric vehicle (PHEV) numbers are only going to increase, and we want to maintain our reputation for taking care of the environment by offering a tailored product for these vehicles, so the users can extract the most from switching to this category. The technology used in EV tyres is still relatively new, and it’s something that will be incredibly important for the future,” Leendertse comments.
So, how do tyres that are suitable for EVs differ from those designed for internal combustion engine (ICE) vehicles? “Many of the characteristics are shared and we are looking for very similar attributes, but there are some specifics for this segment,” explains Leendertse. “BEV tyres are designed to meet the higher loads exerted by this category of vehicle. There is an increased focus on reducing rolling resistance to maximise range whilst also coping with the faster acceleration and higher torque found in EVs. Finally, there are design features such as seamless, continuous sipe edge contact and offset tread grooves to improve refinement as EVs are typically quieter.”
The structural considerations associated with tyres for EVs mean that suppliers such as Falken, one of Sumitomo’s brands in Europe, are having to prioritise different features than those for their ICE vehicle ranges. “For example, due to the higher loads exerted on BEV tyres, we add reinforcing materials in the carcass and structure,” confirms Leendertse.
TESTING TIMES
Noise, vibration and harshness (NVH) also influence the design of EV tyres in a different way to ICE tyres. Leendertse notes: “Internal noise and comfort are very important and, because BEVs have less noise emission, any external noise needs to meet regulations. We have created specific design changes such as the seamless sipe edges and the use of our proprietary Silent Core (specialised noise-absorbing sponges) to achieve this.”
The tyre development expert says that testing is one area that is comparable to traditional ICE tyre development work. “Aside from taking into consideration any specific requirements from car manufacturers, in general, testing is similar to ICE vehicles with the exception of the wear test – because we cannot achieve the same mileage in a day.”
RUBBER REVOLUTION
Naturally, much of Falken’s R&D work is focused on materials. What compounds and mixtures of materials does Leendertse believe are more beneficial for the demands of EVs? “New tailored synthetic rubber – developed in close cooperation with the chemical industry – is key for mileage and rolling resistance, whilst specific profiles and patterns are important as well,” he states. “These are all designed to meet the demands of BEVs as well as offer lower noise levels. For example, we use the Silent Core sponges in our e.ZIEX pattern and this tyre also contains up to 29% of sustainable and recycled raw materials,” he adds.
The e. ZIEX tyre that Leendertse highlights has been something of a success story for Falken since its 2024 launch. He details: “Its asymmetric tread pattern, developed using our Advanced 4D NANO Design technology, features optimised tread edges that prevent pressure peaks by distributing pressure from the tyre smoothly. The tread pattern is also optimised at the contour of the tyre shoulder, lowering its rolling resistance.”
A notable design achievement can be found in the tyre’s smart approach to tackling noise. “Drivers are placing greater importance on vehicle refinement and comfort. Between ICE vehicles and EVs, the difference in cabin noise can be stark, yet the e. ZIEX tyres are engineered to enhance refinement for both powertrains,” reports Leendertse.
Durability was another focus of the e.ZIEX’s development work. EVs typically deliver far greater levels of torque than ICE vehicles, thanks to their instant power delivery capabilities. Applying this increased performance to the road is achieved via the tyres, resulting in more aggressive wear compared with an ICE vehicle. Leendertse points out that tyres must also accommodate the increased weight of EVs – usually 20-30% more than a typical ICE vehicle. “We have worked extensively to optimise the construction of the e. ZIEX tyre, using new materials and construction techniques to ensure it is lighter than a conventional tyre. The tread has been designed to wear evenly to maintain consistent grip throughout its life, enhancing safety and providing budget-friendly longevity,” the expert reveals.
He also mentions that the e. ZIEX tyres are available in the size range of 17-21in and a width of 215-255mm, “to accommodate for the larger brakes usually fitted to EVs to counteract any losses in braking performance associated with increased vehicle weight.”
EV-SPECIFIC SIMULATION
Falken’s parent company Sumitomo Rubber has developed a simulation technique called Tyre Aerodynamic Simulation, which is used in the process of tyre development. On this, Leendertse comments: “To reduce the electricity consumption of EVs, it is very important to minimise tyre rolling resistance as well as air resistance around the tyre. Sumitomo will pursue the development of a tyre shape that optimises aerodynamic performance by visualising the airflow around the tyre of a running vehicle through our own simulation using AI, thereby aiming to develop a tyre that further contributes to lowering the electricity consumption of an EV in a next-generation EV tyre to be launched in 2027.”
