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Old 03-24-2019, 10:34 AM   #2 (permalink)
California98Civic
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Join Date: Mar 2011
Location: Coastal Southern California
Posts: 5,967

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
Thanks: 2,239
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This site offers the formula for how to use tire size to calculate tire diameter:
https://auto.howstuffworks.com/auto-...size-chart.htm

tire diameter:

(CROSS SECTION WIDTH x 0.ASPECT RATIO x 2 25.4) + WHEEL DIAMETER = OVERALL TIRE DIAMETER

For Example:

235/45ZR-17

(235 x 0.45 x 2 25.4) + 17 = 25.327"

And here's a calculator for the rest of your query:
https://tiresize.com/gear-ratio-calculator/
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See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.



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