Quote:
Originally Posted by Joggernot
Well, my tires are in contact with the ground. When in contact with the ground the tread has zero forward motion. The car is still going 45 mph. The only thing on a wheel that is going the speed of the car is the axle. The top of the tire is going twice the speed of the car or 90 mph. Or is my thinkin' stinkin'...?
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On average every part of your wheels is moving forward at the same speed as the rest of your car. So the forward motion part of inertia is equal to fixed parts of the same mass.
Then it also takes energy to spin up the wheel; slightly less than the forward motion requires. The total inertia is the sum of both; slightly less than twice the mass of the wheel.
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2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
  lifetime FE over 0.2 Gmeter or 0.13 Mmile.
For confirmation go to people just like you.
For education go to people unlike yourself.
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