?? about tires size for fuel mileage!!

DITTO! That is basically what my research has found. Even the manufacturers say its currently a matter of preference and location. There is no cut and dry benefit where one out-weights the other. Personally the 22.5 LPs seem to be the best overall benefit. RPM's are negligable from 24.5 tall to 22.5 LP less than 200 rpm. ( have that info posted somewhere), 22.5LP are readily available, lower resistance than talls, good wear milage, fuel milage, etc.