Prior to recalibrating, please delete the controls.cfg file which is located in your Documents/iRacing folder. If you have chosen the option "Use Custom Controls for This Car", you may also need to delete the controls.cfg file located in your Documents/iRacing/setups/%car% folder as well.

You can then recalibrate your controller by launching the SIM (in a Test session for example) and it should then prompt you to recalibrate your controller.

Click Options and make sure you are in the Drive tab
in t
he Input Calibration section, click either Steering, Pedals or Gearbox - depending on what you want to recalibrate