Determination of weight distribution on the axes is based on the measurement of deformation of axle under load. A special load cell is able to register micro-deformations of the axle beam even under the weight of a person. The big advantage is the absence of the influence of spring deflection and its fatigue, which reduces the frequency of recalibration to 1 time per year.
Futhermore VESA Truckload designed for working on trucks with any types of suspension - spring, air, hydropneumatic.
Here is some examples.
You could get customized solutions.