Low rolling resistance (LRR) tires take less power to move and save save energy. Saving energy is important to the battery EV due to limited storage. Since 5 to 15 percent of motor energy is used to overcome vehicle rolling resistance, tire choice can be important.
Many if not all new battery and hybrid electric vehicles come standard with lower rolling resistance tires than gas powered models. Less resistance means better fuel economy which means fuel cost savings. Actual savings seem to be a few miles per gallon or so.
Technically Speaking
Rolling resistance is a result of friction between the road and rubber in the tire and the tire flex induced by driving.
A tires resistance to rolling (RRC) is expressed as rolling resistance / wheel load. The lower the RRC, the less energy it takes to overcome resistance and move the car forward. Typical RRC values range from
0.007 to 0.014.
LRR tires use stiffer rubber compounds designed to lower resistance, and efficient tread patterns. There is a tradeoff in handling, but an improvement in fuel economy with these designs.
One other tradeoff is expense. LRR tires cost more than similar non LRR treads. You may be able to recoup the savings over time depending on cost and mileage.
The Bottom Line
LRR tires come in a range of styles, sizes, and prices. You may or not be able to recover your investment.
We suggest that you check prices on LRR and competing traditional designs before paying a premium.
Example:
The Michelin Energy Saver A/S has been highly rated for good fuel economy. This tire lists for around $100
each for a 195/60-15 tire. A similar Michelin tire lists for around $75.
That gives you a $100 premium for four tires. The question is will you recover that $100 in gas savings of say 2 miles per gallon?
Assume that you keep the tires for 50,000 miles.
Baseline Tire Prius mpg = 51.4 mpg. In 50,000 miles you would use around 973 gallons of gas.
Michelin Energy Saver Prius = 53.8 mpg. In 50,000 miles you would use around 930 gallons of gas.
The difference 973 - 930 = 43 gallons of gas.
At $4.00 per gallon gas saved is 43 x $4.00 = $172. You save $172-100 = $72.
At $5.00 per gallon gas saved costs 43 x $5.00 = $215.
Of course, your experience will vary, but there are potential savings to be had in using Low rolling resistance tires.
