Go to Tuning menu and under Body, there is the Ballast Control.
When you first open it, you will see the silhouette of a car with numbers under the front and rear wheels. These numbers indicate the weight balance at the front and rear of the car. So, if you see 45 front and 55 back, that means 45% of the weight is at the front and 55% is at the back.
There are two sliders. The top slider goes from 0 to 200kg and indicates a weight that will be added to the car.
The bottom slider positions the weight towards the front (-50) or rear of the car (+50). When you want to add weight, you add it and then position it.
Some like to add weight to bring their cars to a 50-50 balance. Other cars may handle better this way, but some cars may also handle better with a little more weight at the front or rear, depending on drive train.
I'm no expert, but for some of my FR cars, I like to add a little ballast weight up front to simulate downforce. You can also use the control to add weight to help it meet a PP regulation.
