Michelin EV tireEnlarge Photo
Customization has been a part of car ownership ever since Henry Ford told customers they could have any color “as long as it’s black.” But while lightning bolt graphics and a kick-ass sound system may be part of your electric car dream, a new set of pimped out shoes could put your cruising to a premature end.
Physics 101: Rolling Resistance
Before we delve into the world of custom rims, fat tires and improper inflation we need to briefly explain a term which physics uses to define the relationship between a moving object and the surface it is moving along: rolling resistance.
In the case of a car tire, rolling resistance is the energy lost due to friction between the tire and the road. The higher the rolling resistance, the harder the car has to work to move itself along. The lower the rolling resistance, the less energy is required.
Today, every car tire on the market from low-riding sports tires to chunky off-road mud-munchers has a measured rolling resistance which is used to give the tire its own efficiency rating.
2011 Nissan LEAF prototypeEnlarge Photo
"Energy Tires" - Lowering Rolling Resistance
As with any vehicle designed to be energy efficient, electric cars are designed to use as little energy as possible when driving along. The less energy they use, the further you can travel per charge.
But while a lot of electric car economy is down to how the car is driven, its tires also play an important part in improving range.
Lowering the rolling resistance of an electric car’s tires reduces the energy consumption per mile, and allows the car to go further.
As a consequence, nearly every electric car on sale today uses specially designed tires, giving the driver as much grip as possible without detriment to range.
We love custom wheels, but when it comes to fuel efficiency you’ll need to weigh up the pros and cons of switching those factory-spec rims to something a little more flashy.
Why? Because custom wheels almost invariably involve larger diameter tires than stock, with wider track and more physical rubber to put down on the road.
Kumho Ecsta SPT KU31Enlarge Photo
What does that lead to? You’ve guessed it: increased rolling resistance.
Not only that, but as far as we know there isn’t a particularly energy efficient tire available for a 22 inch custom rim.
Finally, ride quality is often comprised too, turning a comfortable sedan into a bone-shaking pimped-out boom box overnight.
Check Before You Buy
We’d love to see a range of custom wheels built with low-rolling resistance tires in mind, but for now we don’t think they exist. If you know differently, please let us know in the Comment section below.
For now, however, we think customizing your electric car is probably going to stop at some fun decals, an upgraded sound system, a flashy respray or perhaps window tinting.
And if you really do want custom wheels, make sure you do the math before you buy and ask yourself if range is more or less important to you than standing out from the crowd.