The biggest complaint drivers have about electric vehicles is their range. They might be far cleaner, much cheaper to operate and maintain, and not subsidize murderous dictators, but they can typically go only 200-350 miles on a charge (though some expensive models can top 500 miles). And because the U.S. car charging network is still being built out, that can mean having to carefully plan one’s road trip, having to wait in line at a charger, and so on.
So it’s strange that so many EVs are outfitted with snazzy features that badly sap their range. In particular, the fancy low-profile rims that are very common on American EVs knock their range down by as much as 15 percent. It’s just the most obvious example of how America’s addiction to big, fast cars is an unnecessary obstacle to the EV transition.
Jason Fensky explains the physics of the rim problem at Engineering Explained. All else equal, larger diameter wheels are heavier, which means more rotating mass, which means more energy needed to spin them. A larger diameter means more air resistance (particularly when they come with fancy angular decorations), and more resistance still because they typically come with wider tires. Wider tires in turn worsen rolling resistance, eating up still more energy. According to Tesla, moving from 20-inch rims to 18-inch ones on a Model 3 improves range by nearly 15 percent, under typical conditions.
This matters especially for EVs because batteries are considerably less energy-dense than diesel or gasoline. (Their range is as good as it is because electric motors are vastly more efficient than internal combustion engines.) Where you can compensate easily enough for inefficient wheels in a gas-powered car by adding a couple gallons to the fuel tank, additional battery capacity means a huge weight penalty, which itself saps range.
What’s more, low-profile tires have a considerably worse ride quality because there is less rubber to absorb shocks, and with no protruding sidewall, it’s very easy to damage those fancy rims when parking or driving too close to a curb.
The problem is compounded by the EV manufacturer habit of producing absurdly fast models. Zero-to-60 times for today’s crop of electric automobiles are routinely under five seconds and occasionally at three seconds or less. Now, I can’t blame people for enjoying the thrill of explosive electric acceleration — it’s surely one of the reasons EVs have gained market share — but that is preposterous speed. Sixty miles per hour in three seconds is faster than a 2020 Ferrari Portofino, equipped with a twin-turbocharged V8 making 591 horsepower.
We can see all these problems coming together with the Rivian R1T. This pickup truck starts with a dual-motor setup making “only” 600 horsepower and a 0-60 times of 4.5 seconds, with a range of 270 miles on the base battery. You can increase the range to 350 miles with the medium battery, and 400 miles with the biggest one. But if you option the quad-motor drivetrain making 835 horsepower with the medium battery (the only option available at time of writing) range is cut from 350 to 328 miles. And sure enough, if you pick the 21-inch wheels instead of the 20-inch, range is cut again to 303 miles.
Those battery upgrades are also extremely expensive, because they’re so large. The base battery is 105 kilowatt-hours, while the medium is 135 and the large 180 kilowatt-hours, and so the different options will set you back $6,000 and $16,000 respectively. That huge battery is also why the R1T has a base curb weight of over 7,000 pounds.
The R1T has gotten rave reviews because of its ridiculous speed and high build quality. But it is Caligula-esque levels of pointless excess to be driving a large truck around that is faster than a Ferrari sports car. Let’s be real: In ordinary road conditions nobody ever has a legitimate need to hit 60 miles per hour in three seconds. People who even use that capability outside of a race track are in the best case scenario impressing their friends on a highway on-ramp, or else they are breaking the law somehow.
It should also be noted that the heavier a car is, the more dangerous it is to other cars or pedestrians in an accident, because momentum is proportional to mass.
This isn’t the only way to go, of course. Consider the recently discontinued Chevy Bolt, with a 200 horsepower motor and a 63 kilowatt-hour battery. But that smaller drivetrain and battery means its weight comes in under 3,600 pounds, which together with relatively sensible 17-inch wheels (though I’d go even smaller) enables a perfectly respectable range of 259 miles. (That’s just 30 miles short of the Hummer EV, whose battery is 3.4 times larger.) Smaller and cheaper parts also mean the Bolt’s starting price is also $27,500, compared to the R1T’s $74,000 — and because the Bolt requires far less energy and fewer raw materials to produce, it is far better for the climate.
American drivers are simply spoiled by technology. Two hundred horsepower and 266 pound-feet of torque is plenty for 95 percent of the tasks American drivers actually perform with their cars — indeed, more than is strictly necessary. I remember when my family bought a Honda Accord in 2003, with its 160 horsepower four-cylinder engine, and it felt downright zippy.
It will take more than an article to cure America’s addiction to big cars. But right now, EV shoppers can take a simple and easy step to ease their range anxiety: skip the fancy wide rims.
Courtesy of U.S. Forest Service
