[swartzentruber]

I think I understand pretty well the relation of tire pressure to performance/comfort. A higher pressure tire should give better performance, whereas a lower pressure tire should give better comfort. However, what, if any, is the relationship between pressure and fuel economy. I would suspect a higher pressure tire would give better fuel economy due to a smaller contact patch on the road, and thus less friction. Could someone with good technical knowledge comment?

 

[ajchenmph]

Re: Affect of Tire Air Pressure on Fuel Economy (swartzentruber)

Don't have the scientific data, but you are correct: higher pressure tires (within reason) do give better fuel economy, but at the expense of ride quality. So, find your balance -- you're not going to get oodles of extra MPG's by running higher tire pressures, but it'll be somewhat better.
I tend to run around 35lbs in the front and 40lbs in the rear (+/- about 5 lbs), just in case I take a corner hard, that helps fight the understeer. Still higher than what's recommended in the fuel filler door, for both fuel economy and sidewall flex issues.

 

[W8]

Re: Affect of Tire Air Pressure on Fuel Economy (swartzentruber)

It's not only the smaller contact patch that improves mileage, but the higher pressure increases tire stiffness and reduces tire compression as the tread hits the road, reducing rolling resistance and heat buildup in the tire.

 

[pass-variant]

Re: Affect of Tire Air Pressure on Fuel Economy (W8)

W8 hit it on the head... think of it in terms of energy... Your car has so much kinetic energy which it has received from the go pedal... this energy is absorbed by the tires by flexing them, which results in heating them, which is how the energy (wasted) finally leaves your car. So less flex, means less heat, and that is saved in the continuing motion of the car.

 

[Electron Man]

Re: Affect of Tire Air Pressure on Fuel Economy (W8)

In addition, the use of silicon (with carbon black) in the rubber compounding process can further reduce a tires rolling resistance.
Look for Michelin MXV Green X Plus tires for low rolling resistance.