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Old 04-27-2008, 04:37 PM   #3 (permalink)
EcoModding Lurker
Join Date: Apr 2008
Location: Kampsville
Posts: 77

stinky - '97 geo metro lsi
90 day: 44.71 mpg (US)
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Some general rules?
Contact patch is derermined by air preasure A 22" tire at 32 psi has the same contact patch as a 12" tire at 32 psi
Reciprical weight weighs 10 more. i know this sounds funny. but it takes alot more to stop or start a tire than to say just lift it. Sprung weight is also more than non sprung weight. but that difference is for handling as opposed to mpg
So I guess tires have four variables, weight, aero, rolling resistance, and final drive ratio. those little 12" tires make weight and aero go down. rolling resistance is a smaller variable. then a person can use gears to make the final drive ratio back up. The best tire would be an extremely skinny and big around tire, like a bike tire. unfortunately as the diameter gets bigger, the width and weight gets bigger, and those two overly outweigh the diameter advantages

Last edited by guitarterry; 04-27-2008 at 04:52 PM..
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