Well I don't know if ths is even possible in Assetto because of its simple tyre model.
In ACC we do have a 5 point tyre model. I guess here you would feel the difference.
Here is a great forum article about it.
Do you use a DD wheel? I have the simagic M10 and I can feel a bit of a vibration difference when I test drive the curbs that are a straight line (ex: in front of Karthalle)
btw: I have set the "Kerb effect" to 0% in CM force feedback settings. So the vibration only comes from the mesh itself.