The GRAVIBAL view and knowledge obtained during the development on the possibilitues to use road force compensation when balancing low profile and wheels for heavy cars is presented in short form here.

The road force variation on a wheel is the result of the tires imperfection not providing evenly distributed spring compression of the car towards the road.

The vibrations in the car comes for 2 sources, that are not mutually possible to balance out. The road force variation (tire stiffness) is almost constant independent of rotational speed. The weight imbalance is exponential dependent of speed and grows heavely with high speed.

These 2 sources are not to be mixed up together.

The tire manufactures already measure the fundamental harmonic road force (the Red Dot on the tire) the H1 point.

With the Red Dot available and by doing a runout measurement focusing on the runout curve and not the rim imbalance in weight, then the Red Dot shall be placed on the lowest runout point and an equivalent road force balancing has been made. So for most tires, it is possible to do the same as a road force expensive machine. Ignore the Yellow Dot, as this will be balanced out with the GRAVIBAL wheel balancers as the balance including the runout differences, which is in contrast to the standard dynamical wheel balancers.

Using the GRAVIBAL wheel balancers gives the further advantage that you will not ‘over balance’ the wheel due to the runout imperfection, wich may easily happen on a dynamlic wheel balancer.

It is advised when mounting a new tire to inflate this ex. 4-5 bar, to get the bead settle and deflate to you preferred pressure, before doing the final weight imbalance of the wheel.

In short:

1. When a tire is supplied with the Red Dot, note down and keep the position of the Red Dot for each tire, maybe use a picture. Do a rim runout measurement with the GRAVIBAL wheel balancer and place the Red Dot at the lovest runout value. Ignore the Yellow Dot. This is THE SAME AS A ROAD FORCE machine is doing.
2. If the tire has no Red Dot, then no road force balancing can be made, instead use the Yellow Dot and align with the heaviest point of the rim imbalance weight curve.
3. Having non of these marks because the tire is old, it is likely that the GRAVIBAL wheel balancers will still balance out the road forces, as the normal tires and cars allows for the residual road force (tire stiffness variations) that the suspensions can handle without vibrations to extent into the car.
4. Using GRAVIBAL wheel balancers will not ‘over balance’ wheels due to runout imperfections.

GRAVIBAL welcome all questions and comments back on the topic of balancing wheels including the hubs, compared to balancing part of wheels with a dynamic balancing principle.