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Old 04-10-2009, 06:15 PM   #12 (permalink)
Blue Bomber Man
EcoModding Apprentice
Join Date: Sep 2008
Location: Upstate NY
Posts: 190

GreenMile - '00 Mazda Protege ES
90 day: 34.45 mpg (US)
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Thanked 5 Times in 3 Posts
My opinion should be taken with a grain a salt but:

Generally speaking larger diameters tires have lower C_rr according to the government study previously mentioned. It will also improve you gear ratio for highway speeds.

Acceleration losses isn't entirely accurate, its more like deceleration losses. More energy is tied up in the wheels, but it's not lost until you decelerate. If you are efficient about hypermiling your additional losses from the increased MOI should be offset by the other increases.

If you were to ignore the changes to your gearing ratios I would only consider C_rr if you access to the information. Like I said earlier larger tires generally have lower C_rr but the lowest value I have found (and this is an official number) is the Bridgestone B381 with a value of .0065 which is about 35% lower than average. However the tire was a 14 incher if I remember correctly.

Look up the Californian/Federal study on Rolling resistance it is extremely informative. I think the first 40 pages was random crap, but it gets to be very educational later on.

Good luck with your search!
'Blog' on the open source electric motorcycle project.

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