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Old 06-11-2011, 05:07 PM   #13 (permalink)
bwilson4web
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Quote:
Originally Posted by California98Civic View Post
So the 185's rev a little more than 2% less than the 175s?
You mean fewer revs and the correction should be relative to the stock tire, assuming it is the 175/70R13:
(907-927)/927 = -2.16%
Quote:
Originally Posted by California98Civic View Post
That should mean the difference between these two tires in terms of MPG at 5th gear highway speeds would be a little over 1% maybe?
Only if GPS speed limits are being used. Changing the tire size also impacts distance measured and indicated speed. A slower turning tire will lead to a lower indicated speed so drivers are tempted to drive a little faster and into higher, aerodynamic drag.

Quote:
Originally Posted by California98Civic View Post
In a car like an 80's CRX that's possibly a difference of 1.5-2.0mpg at highway speeds, no? If true and the 185s fit my CRX, that's what I would buy. SentraSE-R and others, such as arcosine, seem to have found that despite the larger sizes (worse aero) and heavier weights, that the taller gearing is a net benefit (on the highway, at least).
I'd have to see their data but I don't see anything wrong as long as the same-speeds were used.

Bob Wilson
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