3 things every EV driver should know about their tires

How you fuel up isn’t the only thing that changes when you start driving electric.

Drivers curious about electric vehicles already know they’ll have to grapple with range anxiety and the practicalities of charging at home or on the go. But they’ll also need to pay attention to where the rubber meets the road: EVs stress their tires in different ways than internal-combustion-engine (ICE) vehicles do.

To get a handle on this aspect of the ongoing shift to electric vehicles, Canary Media called up someone who’s spent the last 20 years thinking deeply about tire design. Russell Shepherd is Michelin’s technical communications director for passenger car tires, and he previously spent years working on research and development for the French tire manufacturer.

Michelin’s internal studies found consumers may not be aware of the ways that EVs affect tire performance. Shepherd recommends that people spend more time asking about what tires they’re going to get during the EV-buying process.

“When you’re in a vehicle, the only thing between you and the road is your tires,” said Shepherd, who is based in Greenville, South Carolina.

Michelin, of course, wants to be the beneficiary of that additional customer attention. The company produces tires specifically designed for EVs, and it says eight of 10 major manufacturers put Michelin tires on their EVs for the U.S. market. Other legacy tire makers are getting in on the EV-optimized tire market too, including Bridgestone, Goodyear and Pirelli.

No matter which brand a driver chooses, they need to understand how the switch to electric changes the behavior of tires. These changes don’t require fundamentally different tires, but they do prompt new tradeoffs that a lot of drivers haven’t yet had to think about.

In theory, EV makers are already optimizing for these conditions with the tires they sell on new vehicles. But it’s always worth checking to make sure. And as used EVs proliferate (perhaps with the help of a new tax credit), more drivers will have to decide which tires to buy, without an automaker guiding them. 

Here are three things Shepherd recommends keeping in mind when considering tires for EVs.

That’s so heavy: EVs weigh more than gas-powered cars

Conventional engine blocks are heavy. But even without them, electric cars are heavier than equivalent ICE cars thanks to their super-dense battery packs. An EV will put about 20 percent more weight on its tires than the equivalent gas-powered vehicle, Shepherd said. 

That sounds stressful for the tires. But Shepherd explained that’s not quite how it works.

“It’s not the tire that holds up the car; it’s the air,” he said. ​“EVs tend to have higher air pressure” in their tires.

New EV drivers should familiarize themselves with the recommended tire pressure instead of sticking with the levels they maintained in previous cars. And if you’re the kind of driver who doesn’t regularly check up on tire pressure, acquiring an EV is a good time to update your automotive hygiene. With all the time you won’t be spending getting oil changes or replacing catalytic converters, you should easily be able to fit it in.

Don’t slow your roll: Tire efficiency matters more for EVs

The efficiency of a tire affects overall performance more with an electric drivetrain than with a gas car.

In tire-engineering terms, the quality to pay attention to is rolling resistance, which measures how much energy a tire consumes in the process of rotating. Here’s another way to visualize it: If you stand up a tire on its own and give it a push, it will roll for a bit before coming to a stop; how far it goes before stopping is a visual indicator of rolling resistance. 

Casual drivers never had to worry about minimizing rolling resistance, though corporate fleets eking out every last bit of fuel economy paid attention. Now, anyone driving an EV has good reason to care.

Rolling resistance makes a more tangible difference in EV performance because the vehicles are so much more efficient than combustion vehicles. Gas-burning cars have something like 2,000 moving pieces in their drivetrains, each of which generates friction and gobbles up some of the energy produced by the engine. EV drivetrains only have around 20 moving pieces.

“The simplicity of an electric vehicle allows you to put more of the energy onto the road,” Shepherd said.

Tires eat up about 5 percent of the energy an ICE vehicle generates. But in the more streamlined EV drivetrain, tires consume about 16 percent, Shepherd said. That ultimately impacts how far you can drive.

“The type of tire that you pick has an impact on the range of your electric vehicle,” Shepherd said.

A simple way to reduce rolling resistance would be to reduce tire treads — but doing that haphazardly would cut down on traction. Instead, tire companies like Michelin put their R&D efforts into minimizing resistance while maintaining traction and durability. 

Besides picking the right tire, there’s one big thing drivers can do to maintain the best rolling resistance: Keep the tires properly inflated. (See above.)

Torque to me: EV tires wear down faster

Electric vehicles also exert more torque, or rotational force, than equivalent gas-powered cars. 

This happens for two reasons: The highly efficient electric drivetrains deliver sports-car-like acceleration, even in a boxy little compact. That means EVs put more pressure on tires than vehicles that accelerate more slowly. 

EVs also exert torque in reverse through regenerative braking. This is the feature that takes energy from a car slowing down and converts it into a little extra charge for the battery. 

Any type of braking applies torque on the tires, Shepherd said. But EVs do this more often, and they skip the coasting period between acceleration and braking, jumping straight from propulsion to regenerative braking.

“That additional braking does contribute to the faster wear of the tires,” Shepherd said.

This leaves an EV driver with two options: mentally prepare to replace EV tires more frequently, or invest in tires with greater ​“wear” or longevity.