What's the Deal with Electric Vehicle Tires? We've Got Some Answers

 

As electric vehicles continue to grow in popularity, consumers face a deluge of perspectives about the EV ownership experience and requirements. In a vehicle category rife with early-adopter excitement, there’s also a fair share of confusion and misinformation, especially about EV tires. To address these questions, we've put together some information from a variety of sources that you may find helpful.    Question No. 1 – Do EVs really need special tires?  Yes and no, depending on the owner’s performance and safety priorities and expected usage. Here are four basic categories.   Original Equipment EV Tires –EVs are factory-fitted with original equipment (OE) EV tires designed to meet the vehicle manufacturer’s requirements, with a specific focus on EV range and efficiency. While EV range among vehicle brands and models continues to increase, range anxiety remains a focal point mainly due to a still-growing EV charging infrastructure.   “These tires often use efficiency-focused compounds and lower molded tread depths to maximize efficiency and range,” said TJ Campbell, tire information and testing manager for Tire Rack. “EV OE tires also may have a sound-absorbing foam layer to keep certain frequencies at bay. And the tire’s internal structure may have more robust materials or increased lateral support to handle the force of an EV’s increased weight.”   EV-Focused Tires – There are tires that aren’t designed for a specific auto manufacturer application but are designed from the start to meet EV applications. These EV-focused tires may target some specific OE applications, but since they’re not original equipment the tire manufacturers can focus on their performance goals rather than the vehicle manufacturer’s requirements.   Hybrid Design EV Tires – Tire manufacturers may take an existing tire and make changes for EV use (add foam, modify the tread pattern, focus on noise reduction, modify internal structure or use lower rolling resistance compounds).   Conventional Tires – There is no rule stating that an EV owner has to use tires designed for EV applications. Any tire that meets the vehicle’s load, speed, pressure and size requirements can be installed on an EV.

“EV OE tires also may have a sound-absorbing foam layer to keep certain frequencies at bay," said TJ Campbell, Tire Rack tire information & testing manager. "And the tire’s internal structure may have more robust materials or increased lateral support to handle the force of an EV’s increased weight.”   Below: Tire Rack added Tesla Model 3 EVs to its test fleet earlier this year to collect important data through both real-world driving and testing on the its track at its South Bend, Ind., headquarters. The attributes that make a tire a good tire don’t change based on the vehicle’s propulsion. Whether EV or a traditional internal cumbustion engine (ICE) vehicle, drivers need confident dry, wet, and winter traction and want comfort, ride quality, efficiency, and good tread wear. But tires designed for EVs may be better suited to deliver what many EV owners come to expect, such as optimized range and efficiency and minimal noise and vibration. Question No. 2 – So EV range and efficiency is No. 1. How do tires affect these qualities? Three things can affect your EV’s range and efficiency: tire rolling resistance, tire wear and weather.   Rolling Resistance – This is the force needed to keep tires rolling, and rolling resistance varies among tire models. Generally, the OE-spec tire delivers the optimum range and is the safe bet if range is the priority. In private testing of OE EV tires vs. popular replacement market tires, the replacement tire showed an 11 percent drop or 34-mile reduction in calculated range, yet the replacement tire also showed significant increases in performance in dry, wet, and winter conditions.    Wear affects range – As tires wear, mass decreases and compounds harden, and the force needed to keep them rolling decreases. Simply put, range increases as tires wear and rolling resistance decreases. Great, right? Not exactly. The tire’s performance and grip also decrease, so there is a safety tradeoff. It’s common to see EV range drop with new tires, even the exact same brand and model. Private testing showed a 27-mile increase in range with a worn tire compared with a new tire. Replacing a worn set of high-efficiency OE tires with new tires could decrease range by 15 to 20 percent, but again it’s a range vs. increased performance and driving safety tradeoff.   Weather also affects range – EV owners know that running the heat when it’s cold and the AC when it’s hot robs battery power and affects range. However, outside and road surface temperatures, as well as rain, can affect range, too. Rain often comes with wind, requiring more energy to move the vehicle, and calm rain also decreases range because it takes more power to move the tires through the street surface water. Private testing showed a 27-mile drop in calculated range in dry vs. wet testing. Even if dry, cold temps can impact range. Experts tested the exact same tire in 36 and 61 degree outside temperatures and recorded 235 and 292 miles in calculated range, respectively, further indicating that weather and conditions do impact a tire’s range efficiency.   And there’s more – Another factor to consider is driver behavior. Whether an EV or an ICE vehicle, aggressive acceleration, cornering, and braking will increase tire wear and structural stress, along with reducing range or miles per gallon (MPG). The attributes that make a tire a good tire don’t change based on the vehicle’s propulsion. Whether EV or ICE, drivers need confident dry, wet, and winter traction and want comfort, ride quality, efficiency, and good tread wear. But tires designed for EVs may be better suited to deliver what many EV owners come to expect, such as optimized range and efficiency and minimal noise and vibration. Question No. 3 – Do EV tires wear out faster than non-EV tires? Yes and no. Tires on EVs tend to wear out more quickly than when installed on a comparable ICE vehicle. So it’s not that EV tires wear faster but rather that tires wear faster when installed on an EV. The commonly quoted figure in the tire industry is 20 percent less wear life with an EV vs. an ICE vehicle.    And different factors contribute to this wear, such as an EV’s increased weight vs. a comparable ICE vehicle, and also changing driving habits related to an EV’s instant torque and acceleration. Again, according to Campbell, there are tradeoffs. “If you have a tire that’s hyper focused on efficiency and therefore range, it might sacrifice wear, among other desirable characteristics.”