The measured loaded tire diameter (displayed for each tire/wheel assembly) can also 
affect the pull condition. A significant difference in these measurements may indicate 
under/over inflation in a tire or a mismatched set of tires. 
Another common factor that can affect steering pull or drift in relation to the tires is 
the variation in air pressure of the two tires when compared side to side on a given 
axle. Tire pressure measurement is prompted with a pop-up screen before every load 
roller measurement. 
GSP9720JLR Wheel Balancer Operation Instructions  Theory of Operation 
 143