Not Ranked
285/40R17
285 * 0.40 = 114
114 / 25.4 (mm per inch) = 4.49" sidewall height
4.49 * 2 = 8.98" (top and bottom sidewall)
8.98 + 17" rim = 25.98"
So, I think your tire height is 25.98 instead of 26.97.
25.98 * PI = 81.61" circumference
( 4.1 * 12 * 5280 * 60 ) / ( 81.61" * 60 ) = 3183 RPM
So assuming the real speed was 60 (and that your 4th gear is indeed 1:1, which I think is right), then your were turning 3183 RPMs.
Sorry I don't know how to fix it, maybe somebody else can help.
Last edited by Paul Rose; 01-02-2002 at 01:54 PM..
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