Just bought new tires and wheels for my 06 GTO and wanted to adjust my speedo settings to be more accurate because of the change. However, when I first went in to the Speeo Calculator I started off by entering my OEM tires into the calculator and the results were not even close to the OEM values in the tables. For example, for my stock 245/45/17 wheels (corrected tire size 3/1/07 @ 10:07 pm MST -- was 245/25/17):
Param: -> OEM Val -> Calc Value
H0101 -> 11792 -> 67536
H0104 -> 312 -> 1688.39 (the calculator inserts 636 here when apply is pressed)
H0136 -> 503 -> 487.98 (nothing happens here when apply is pressed)
H0139 -> 2540 -> 2049.26 (nothing happens here when apply is pressed)
Before I go entering the data for my new tires/wheels and really mess things up. I'd like to understand what's going on.
Any thoughts?