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Old 08-09-2009, 12:44 AM   #19 (permalink)
cfg83
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Join Date: Dec 2007
Location: Southern California
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1999 Saturn SW2 - '99 Saturn SW2 Wagon
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RandomFact314 -

Quote:
Originally Posted by RandomFact314 View Post
I have a gps but I already have gotten rid of those tires
Hrmmmmm, I apologize for not reading more closely. Even with the tires you have on now, I think you should do an odometer correction test to see if your odo is accurate.

If I were you I would :

1 - Do the GPS odometer correction test on your current setup. Let's say for the point of example that your odometer is incorrect by -1% in your disfavor.

2 - Instead of +10%, make it +9% to be "conservative" in your estimate (because you can't prove it with test data). My wife's GPS shows greater than 2.5%, but I only give myself a 2% credit. I do this to insure that my claimed benefits are well within the range of error.

3 - +9% + -1% = +8% Correction.

4 - Go over your fuel logs and add the data in. I put tons of info my "details" section of my fuel log :

Quote:
Ignore high/low MPG, only look at AVERAGE MPG (Chevron;91 Octane;#1). 181168 miles on odometer. Tires are larger, so odometer is reading 2% less, hence +2% correction: 248.7 * 1.02 = 253.674
But that's just me. YYMV. (Your "You" May Vary)

CarloSW2
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Last edited by cfg83; 08-09-2009 at 05:46 AM..
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