Here is a link to a good explaination off load force balancing.

Tire Tech Information - Tire & Wheel Package Ride Uniformity Confirmation

Basically it matches the tires to the wheels, since there are high and low spots on the wheel it will match a low spot on the tire to a high spot on the wheel and also the opposite. You will be amazed at how well your vehicle will ride and respond once you get the wheel mated to the tires.....it a WOW factor of 10! hope this helps
Bob