Thread: Prius 75-91mpg
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Old 04-22-2019, 10:06 AM   #23 (permalink)
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Originally Posted by Ecky View Post
You might be surprised to learn, but I did some math yesterday and it turns out the inertia of a wheel actually goes down as the aspect ratio (and thus overall diameter) goes up, because it spins more slowly. So, in effect, a 165/80r14 tire is "lighter", inertially speaking, than a 165/40r14.
You mean angular momentum? Rotational inertia is independent of speed.

All that as a prelude to saying, I don't get that result using representative tire dimensions and weights from Tire Rack--for the 185/55R14 and 185/75R14 I compared just now (they don't list any 165/xxR14), the larger tire still has higher angular momentum....

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