Why does people who play with a pad have to adjust steering deadzone, sensitivity etc are these not wheel settings? I have never come across a racing game where you have to adjust so many settings for a pad.. this could be the reason people are struggling because the game was designed around people who use a wheel? And I have still not found the right settings for the pad I use and it's fustrating me as I can't enjoy the game
Have you checked this thread for pad settings? https://www.gtplanet.net/forum/threads/dualshock-4-steering-settings.328144/
Even if you're not using a PS4, the most relevant settings for smoother steering should probably the same on other platforms.
I'm actually back to playing primarily with the Dualshock 4 after some mildly satisfying tests with my cheap - and annoying and potentially slightly faulty - Thrustmaster T100 wheel.
With the right settings and a fairly gentle thumb, Project Cars plays really well on a gamepad (some cars easier to handle than others for obvious reasons). At least it does on the PS4.