Go to the Main Menu and select Options. Under Game Settings, make sure Stability Help is off. Launch a Quick Race, Championship Race, or Career Race. Once you are in the cockpit of your car on pit road, look at the bottom of the screen. You will see the option to Change Setup. Select that option and follow the instructions on screen to create your ideal setup. You can choose an existing setup or create your own. You can have 1 custom setup for Qualify and one for Race, per track, per series.