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Old 07-22-2013, 04:49 AM   #33 (permalink)
HypermilerAX
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Join Date: Apr 2011
Location: Southern France
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AX - '95 Citröen AX

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Quote:
Originally Posted by mcrews View Post
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.
I'm not talking about 0.2% but 2%. With the margin of error (the biggest being 2% larger, the smallest being 2% smaller) the real difference can be as high as 6%. How can you argue that? Calculate yourself.

In that case, the biggest tire has lower mpg so it goes in the wrong direction (due to the weight). The point was that 2% gearing change can very well change things at 0.1 mpg.

Quote:
Originally Posted by mcrews View Post
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
No passive-aggressiveness please. I was talking about how it should be ideally not what you ought to do.
Of course you can improve mpg with the tires but changing the differential ratio and keeping the same tire size will be more beneficial (no, I don't tell you to do it).
My initial question was "why tall tires" ?
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Citroën AX 1.5 D 430.000 km
Peugeot 307 SW 2.0 HDI 136 195.000 km

Last edited by HypermilerAX; 07-22-2013 at 04:54 AM..
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