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Old 07-21-2013, 09:22 PM   #24 (permalink)
mcrews
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Location: Texas
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The Q Sold - '02 Infiniti Q45 Sport
90 day: 23.08 mpg (US)

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Quote:
Originally Posted by HypermilerAX View Post
The thing is that the tires do NOT have the same diameter. They even say it : "speedometer error". There is 2% difference and that cannot be disregarded when you're measuring something at 0.1 mpg.



Why tall? Because of better rolling resistance? Taller tires are heavier and make worse aero. Big gearing should be done with the gearbox, not the tires.
False.
The 2/10% error in size is within the margin of error. If you have followed any of the multiple threads on taller tires, we all agree that you need to be atleast 5% increase to accurately explain the increased mpg.

shoulda, woulda coulda......you paying the bill for new gears?????
MANY members here use taller tires to improve mpg by lowering the rpm at cruise. Please see my threads on my Infiniti Q45 245/45/18 stock to 245/50/18. Same improvement on my KIA Sportage 235/60/16 stock to 235/70/16

Taller tires barely weigh 1 lb more. and do not measureably increase aero.
But I'll Take my proven gain in mpg (along with the other proven result from other members) all daylong over a 'precieved' reduction in aero.
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ECO MODS PERFORMED:
First: ScangaugeII
http://ecomodder.com/forum/showthrea...eii-23306.html

Second: Grille Block
http://ecomodder.com/forum/showthrea...e-10912-2.html

Third: Full underbelly pan
http://ecomodder.com/forum/showthrea...q45-11402.html

Fourth: rear skirts and 30.4mpg on trip!
http://ecomodder.com/forum/showthrea...tml#post247938
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