Thread: Tested rpm-mpg
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Old 05-20-2011, 05:47 PM   #4 (permalink)
bwilson4web
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Quote:
Originally Posted by BHarvey View Post
I ran a test for baseline and did it 3 times to verify.

57 mph on cruise on a 10 mile stretch with a couple decent climbs/descents.

6th gear= 2000 rpm and 49 mpg
5th gear= 2490 rpm and 44.5 mpg
4th gear= 3000 rpm and 39 mpg

Seems to show that less rpm is certainly better. I have room to go up on tire height but 27.5"-28" OD would be maximum. Current tires are 25.5" OD so around a 10% reduction in tire rpm will net how many less rpm's?
When you change tire diameter, any vehicle specific MPG meters will be off as will the speedometer. You'll need to recalibrate or use a correction factor, 10%, to be able to compare with your baseline.

LATE THOUGHT: Rather than buying four new tires, buy one and a full-size rim. Then put it on a front and later rear wheel to test for interference. It is a lot easier to 'eat' the cost of one tire than four.

You can also get just a second tire and then put them on the drive wheels. Often this is enough to test your hypothesis about revs/mile and vehicle efficiency without having to put so much money into tires.

Bob Wilson
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Last edited by bwilson4web; 05-20-2011 at 06:00 PM..
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