Some of the higher-end machines are simple to arrange and often have an arm that extends and comes in contact with the rim, taking all of the measurements. On older or more fundamental balancers, you have to use a caliper to measure the diameter, then enter the numbers and select the sort of balance manually. It is necessary to make sure the numbers are correct as an inch can affect the stability considerably. Likewise, the beneficial process for many alloy wheels is to position the cone within the bottom of the wheel.
This is a good option for a repair …