When driving an electric car, it\’s important to consider the only part of the vehicle that actually touches the road.
Tires can have a major impact on electric car range. Automakers often fit electric cars with low-rolling resistance tires to maximize range, albeit often at the expense of handling, as these tires offer less grip than conventional tires. That tradeoff appears to be worth it, however.
As a number of back-to-back tests have shown, seemingly subtle differences to aerodynamics and rolling resistance can have a serious affect on efficiency—and thus range.
Even small differences are noteworthy when it comes to range. A difference of 10% isn\’t likely to go noticed by an internal-combustion car driver. But it can make a difference in usability for EVs.
A recent Road & Track test showed that sticky performance tires reduced the range of a Volkswagen e-Golf by nearly 20%—leading one to wonder whether they\’re worth the handling improvement.
The magazine swapped the VW\’s stock 16-inch aero wheels and Bridgestone Ecopia EP422 tires for 18-inch wheels (with a less aerodynamic design) and Michelin Pilot Sport 4S tires.
2019 Volkswagen e-Golf
The Pilot Sport-shod e-Golf managed an impressive 1.0g on a skidpad, compared to 0.77g for the stock and wheel-and-tire setup. But while the stock e-Golf has an EPA-rated 125-mile range, observed range dipped below 100 miles with the stickier rubber.
It\’s not just tires. The wheel design can have a significant role in boosting efficiency. Car and Driver found last year that just using Tesla\’s aero wheel covers on a Model 3 improved its efficiency by more than 3%—or about 10 miles of range.
That confirmed what Green Car Reports has noted before in a tire swap on a Chevrolet Bolt EV—and a corresponding range drop of roughly 10% with the higher-performance rubber.
Tall, skinny tires used to be the trend for green cars, but more recently low-rolling resistance tread patterns and new compounds have helped reconcile some of the conflicting priorities.
Several concept tire designs also promise to recover or generate energy for use by the car in some future that remains likely many years off.