Better Wheels

Rolling Resistance

We have a soft spot for the past, present, and future of tires.

(Not that we’re in favor of the tires themselves having soft spots.)

In the quest for fuel efficiency, lowered pollution, and a counterpart to planned obsolescence when operating 18-wheeled commercial trucks hauling freight throughout the country, literally fueling and driving so much of the national economy: it’s the tire that serves an oh-so-essential function.

Why is the better-mousetrap-approach to tires so important? Inflation.

As in: air pressure. Air escapes, and drivers need to re-inflate regularly. According to Goodyear, under-inflation is

“the number one cause of premature tire removal. Under-inflated tires build up excessive heat that can result in tire destruction and/or improper vehicle handling. In addition, it can result in irregular wear and poor fuel economy. If a fleet invests in low rolling resistant, fuel-efficient tires and then does not maintain the optimum inflation pressure, they may not benefit from the fuel economy expected.”

So, it’s a challenge.

Along comes the airless tire: solid rubber and composite that can withstand more wear and tear and never needs inflating.

A lot of focus here is on “rolling resistance” ⏤ friction created between tire and roadway. Or, as Consumer Reports puts it, rolling resistance is “the energy it takes to rotate the tires, affected by the friction caused when the tire surface meets the road. The Department of Energy estimates that 4 to 11 percent of fuel consumption is due to tire rolling resistance.

Airless tires could reduce fuel consumption because they would have lower rolling resistance.

No flat tires. No need for a spare tire. A reduction in CO2 emissions.

A better mousetrap? Maybe. The tire innovators are still figuring out how to compensate for the heavier weight of the airless tire, and the (for now) higher price point, and the extra heat that right now is dissipated better via air in the tire. These are all worthy goals and challenges.

With all due respect to South Carolina motto: let’s hope for a time when we can tread on them.