- the tesla model 3 comes standard with aero covers that shield most of its 18-inch wheels. we wondered: just how much of an efficiency gain do they provide?
- so we went to the chrysler proving grounds' five-mile oval track to test the model 3 back to back with and without the covers.
- they improved the model 3's efficiency by more than expected, an average of 3.4 percent across speeds of 50, 70, and 90 mph and a boost in range of up to 10 miles.
although views on their aesthetic appeal vary, the tesla model 3’s standard aero wheel covers should in theory reduce turbulence and wind resistance, thereby reducing consumption and boosting range. but by how much?
the aero wheel covers are immensely lighter, as the snap-on plastic piece that they are, rather than if the wheel was designed to look like this, with just five small openings between thick spokes. tesla made our test relatively easy because it sells a $50 accessory package of center caps and lug-nut covers to enable owners to expose the arguably much better-looking multi-spoke aluminum wheels beneath the stock covers.
recently, we took our long-term model 3 long range dual motor to the chrysler proving grounds' five-mile oval track to put the aero wheel covers to the test. we conducted the test under controlled conditions: the ambient temperature was a consistent 44 degrees fahrenheit, tires were set per the door placard specification of 42 psi, hvac controls were set to 72 degrees on auto (this is done for all of our highway fuel-economy tests as well), and, most important, there was zero traffic and no elevation to skew the data. tests were conducted back to back, and for each one we did two loops of the five-mile oval. to see how the aerodynamics change with speed, we tested both with and without the wheel covers at 50, 70, and 90 mph, tracking the watt-hours per mile (wh/mile) using the onboard consumption meter. we then repeated each test a second time to ensure accuracy; the figures we're reporting are an average of those two tests.
starting at a constant gps-indicated 50 mph, we measured 258 wh/mile with the aero covers off, and 250 wh/mile with them fitted. that's an impressive 3.1 percent reduction in consumption and suggests a boost in total range from 312 miles to 322. at 70 mph, the results were similar, with an indicated consumption of 318 wh/mile falling to 310 with the aero covers on. that calculates to a reduction of 2.5 percent and a boost in range from 253 miles to 260. not surprisingly, we saw the greatest difference at 90 mph, where the aero covers sliced through the air to the tune of 405 wh/mile compared to the uncovered number of 424 wh/mile. that’s a 4.5 percent decrease in consumption for the covered wheels, resulting in calculated ranges of 190 and 199 miles, respectively.
although it may not seem like much, the aero wheel covers proved to be 3.4 percent more efficient across all three test speeds, which is a sizable gain in the automotive world. that's about as much of a gain as switching to a continuously variable transmission or low-rolling-resistance tires, and more than adding an engine stop/start system. although opinions might vary on their looks, the aero wheel covers improve efficiency and range by enough that owners should think twice before ditching them.