The suspension is one of the most important parts of a rally car and it's no ordinary off the shelf suspension either. It's the link between the wheels and the rest of the car and it needs to be able to absorb the huge forces and loads the rally car takes when driving over rough dirt roads and comes flying off a crest to land 20 meters down the road.
Just as the suspensions system is a very important part of a real rally car, the suspension physics simulation of a car in a rally game is also very important. If it's not working right or not working well, it will be so much more difficult to control the car and that means time lost on the rally stage.
In our rally game we are developing, Rally Shift 2, we want to simulate the suspension system just as it works in a real rally car. That includes settings the player can adjust such as spring force, progressive force, compression and rebound damping, etc.
This video shows some of the early work on the suspension physics. It also illustrates the hilarious results you can get when there's a bug in the suspension physics and things are not working quite as they were supposed to.
The suspension physics is still a work in progress and more features need to be added and then tested and fine tuned as the development of the game is progressing.