On a recent trip in my new purchase-2011 LT 5spd-I noticed a discrepancy between the GPS and the car's speedometer. My 15" wheel equipted Aveo ALWAYS read 2 mi/hr SLOWER than the Garmin. My theroy is that the 15" wheel uses the same calibration as the 14" models. Thus, if one is traveling @ 65 car speed, radar would show 67mph.Someone put your GPS to work in a 14" wheeled Aveo and LMK the results. Thanks!