[rohrmann]

If the tires were directly under your highest point, such as the front air conditioner, your height would indeed be that much higher. It is more likely your height did not increase due to the front air conditioner being close to the pin box/hitch location. Your back end of the rig probably did rise up a measurable amount, but not the important clearance height. If you had put taller tires on the truck, that would increase your height.