by Robert Farago

I am not the world’s most mechanically-minded person. Nor am I the world’s worst. But I’m definitely closer to the latter than the former. For example, I can’t make head nor tails of the above formula, even with the following guide [via howstuffworks.com]:

The letter v represents the velocity of the car, and the letters a, b and c represent three different constants:

The a component comes mostly from the rolling resistance of the tires, and friction in the car’s components, like drag from the brake pads, or friction in the wheel bearings.

The b component also comes from friction in components, and from the rolling resistance in the tires. But it also comes from the power used by the various pumps in the car.

The c component comes mostly from things that affect aerodynamic drag like the frontal area, drag coefficient and density of the air.

Bottom line? “if you double your speed, this equation says that you will increase the power required by much more than double.” Yes, yes, but the question was “What speed should I drive to get maximum fuel efficiency?” Can TTAC’s Best and Brightest provide the required dose of enlightenment, either specifically or generally?

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• Cdotson on Sep 29, 2008