As the title really, If you set the ffb to custom you could have some issues with ffb if you do not tweak the ffb_custom_settings.txt. The Custom setting is designed for advanced users who want full control over what the ffb is doing.
Jack Spade is already making custom files for people to use if you like his setups
http://forum.projectcarsgame.com/showthread.php?51628-Jack-Spade-Custom-FFB-Files
Jack Spade is already making custom files for people to use if you like his setups
http://forum.projectcarsgame.com/showthread.php?51628-Jack-Spade-Custom-FFB-Files