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So it's time to replace your electric car's tires, or it will be soon. You probably won't be surprised to learn there are some important things to consider during the process, things you might not have had to take into account when buying tires for your previous, non-electric cars. Here are some potential pitfalls or mistakes to avoid when buying new tires for your EV.
Don't Dismiss The Tires Already On Your EV
Perhaps the biggest misunderstanding people have about cars in general today, and especially electric cars, is that tires are just interchangeable, Lego-style bits. While it's true that there are likely several different brands of tire that will fit your car, it's also true that the tires that came with your car are the ones it was designed to use—often, in the case of EVs, they're tires that were designed specifically for your car.
It's not just the tire's grip, or noise, or efficiency that come into play when it comes to EVs, but all three—that's why tiremakers and carmakers alike often spend a huge amount of development time and money fine tuning those factors into optimal tire packages for new electric cars.
So when the time comes to replace your tires, for the majority of EV owners, getting another set of the tires that your car came with off the showroom floor is usually the right move, according to Russell Shepherd, technical communications director for Michelin, North America, Inc. "If you're satisfied with the performance of the tires on your vehicle and you want to maintain that performance, then your best option is to buy the OE [original equipment] tire again," said Shepherd. "That being said, there are always interesting options other than the OE one."
Navigating Pitfalls To Find The Right Tire For You
Many of the interesting options for today's crop of electric vehicles are UHP, or ultra-high performance tires. While such tires can help put even more Ludicrous in Ludicrous Mode, they also can represent another potential pitfall in electric car tire purchasing: Making tradeoffs that can lead to unintended consequences.
It's entirely reasonable to want to increase the amount of grip your high-performance electric car offers, and the easiest, most cost-effective upgrade to any car's grip, electric or otherwise, is usually a tire upgrade. But with electric cars, there are some special considerations that can make even foreseen tradeoffs more impactful than they might be in a conventional internal combustion engine (ICE) vehicle.
Rolling resistance, for example, is a much more important element in an EV's overall power loss profile, ironically because EVs are so much more efficient than ICE vehicles—because there's not a huge amount (about 75 percent) of energy being wasted to heat loss and other drivetrain friction, the relatively small amount lost to rolling resistance is a much bigger part of the total picture.
So while upgrading your ICE sports sedan to UHP tires might have reduced your gas mileage by only a few percent, a significant change to rolling resistance can result in larger reductions to your electric car's range. "Keep in mind that tires designed for OEMs and in particular for electric vehicles, are typically lower in rolling resistance. When you switch from the OE tires to replacement market tires, the rolling resistance is probably going to increase," said Shepherd.
As Shepherd explains, changes to grip and rolling resistance aren't the only unintended consequences you might see from changing to a different specification of tire for your electric car, however.
Accelerated Wear And Unwanted Noise
According to Shepherd, EVs are typically about 10 percent heavier (on average) than their ICE counterparts "and so they can wear the tire up to 20 percent more." That's a significant difference in wear and tire longevity, and one that might not be immediately apparent to most EV owners, especially given the unintuitive relationship between slightly more weight and significantly greater wear. Weight isn't the only wear factor, however. The on-demand torque EVs provide and regenerative breaking can also lead to adverse effects on your tires over time.
But if you opt to replace your EV's OE tires with another type of tire, especially one not designed for electric cars, you may open the door to even more noise than you expect. Why is that? Because EV tires are designed with noise—or noise suppression—in mind, much more so than any ICE-vehicle tires. The extra-quiet operation of a battery-electric car's powertrain means there's much more opportunity for road and tire noise to invade the cabin, putting an even greater emphasis on the importance of choosing the right tire for your specific car.
"Many electric vehicles have this acoustic damping foam which is in the tire to dampen road noise, because in electric vehicles you don't have any engine noise, so it's quieter," explained Shepherd. "So if you leave the OE fitment and go to an aftermarket fitment, you may not have that road noise dampening."
That may or may not be a problem for you depending on your sensitivity to tire and road noise and the types of roads you typically drive over. On the flip side, if you feel like the tires your car came with seem too noisy, it may be worth trying a new replacement set for your EV that comes with acoustic damping foam or other advanced technology designed to help reduce noise.
Double-Check The Tire's Load Rating
What can be a problem for anyone, however, is load rating. A new "high load" tire standard—abbreviated HL, appropriately—has been developed to help meet the needs of the EV market, especially in regard to the increased weight necessitated by large battery packs. "[New EVs] are tending to be heavier, and some of these electric vehicles now are coming out on a new standard of high load carrying tire," said Michelin technical product communications and development engineer Steve Calder. "So one potential mistake is not to notice that and put on a tire that's not rated to carry the load even though dimensionally, it's the same size."
Load rating might not be something you'd normally think about, especially with a typical passenger car as opposed to a vehicle you might load with heavy cargo or use for towing. But a full load of 4-5 adult passengers and, perhaps, some luggage can quickly increase the weight of a car by 500-1,000 pounds or more, making the load rating of the tires especially important—after all, safety is even more paramount with a car full of friends or family. A tire's load rating is directly related to its safety, because it ensures a tire can withstand the strains and stresses placed on it during braking, cornering, and acceleration, as well as over bumps and surface irregularities.
At the end of the day, tires might seem like relatively unimportant, easily swapped parts of your electric car, and potentially even a place to save a little more money on maintenance. But in truth, your electric car's tires are of paramount importance, as they're the only contact point between your car and the road, and therefore have a significant influence on your car's safety and handling as well as its overall efficiency and range.