To get a more accurate tire size measurement you should inflate a rear tire to the pressure you normally run. Then measure from the ground to the center of the axel (hub) and double that number for your tire diameter. This then will account for tire deflection while driving and eleminates concern for tire wear etc. Front wheel tire deflection would be different due to weight of engine. Another point, you should have your normal load such as fuel, passengers, stuff in trunk etc. to get normal deflection on rear tire. PK
