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Old 11-17-2012, 03:47 PM
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jr_tech jr_tech is offline
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Quote:
Originally Posted by wa2ise View Post
As I now (mis)understand it, overdrive is when the car tires rotate faster than the engine crankshaft. Which makes sense to do only at highway speed.
No! you neglected the final drive reduction ratio, on the order of 2.5 to 4 :1. Do the math... If you have a tire that is 2 feet in diameter, the circumference is about 6.3 feet... if it was turning, say 2500 R.P.M. , that would be almost 16,000 feet per minute, or about 3 miles per minute!

jr
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