@Davo: spring effect and damper effect strength should really be set to zero as far as I am concerned, but if you like it that way, it's fine of course.
@Flight: Yesterday I tested what you described to see if I have the same problems with my DFP and only didn't notice them before, but I must say, it's really hard to tell. I took the FOX on As club reverse and fooled around a little, went over the curbs as often as possible, trying to keep the wheel straight or turned. And one thing I know for sure is, when I hold it straight and have front wheels loaded (under braking f.e.), rumble strip feeling is quite pronounced. However, when front wheels are not loaded (under acceleratrion f.e.) there is almost no rumble present. Also, I'm certain that I do feel the rumbling when the wheel is only turned slightly and at least one front wheel is loaded (under cornering for example). Where I couldn't really feel anything was, when I turned the wheel quite a lot while going over the curbs. But I would need a more scientific approach to be able to tell if there really is no rumble. Problem is, that it is affected by so many variables like grip or the load on the wheels. Also, it seemed to me, that the curb itself may make a difference. I'm not sure if they are all modelled in the same way (on some, the teething might be rather pronounced, while it might be only very subtle on others). Overall, I do think that the feeling is very nice, though. It does feel very realistic to me and very informative. I also think that the rumble effects could be a little stronger, though. But that's probably because I'm using only 20-30 % ffb strength ingame and 103 % in the profiler.
And one more thing: I haven't tested it recently, but I remember feeling the train tracks on the SO tracks through the wheel, no matter if it was turned or not. So, if that's there, I would assume that the curb-rumbling is also there.
Well, this post is not much help, I guess, but maybe I'll find the time to do more extensive testing. And in case you will be doing more testing, make sure to try it on a curb that's on the outside of a turn in order to have at least one front wheel loaded as much as possible.
No it is because DFP is shitty wheel and very slow. Some say that there is also no delay when you turn wheel to when game is noticing this steering input but there clearly is delay there too, different games do have different length delay actually. Even PES6 has delay of input everything what I do is happening bit behind, take video camera and record steering input and then play it in slow motion and you see how your wheel is turning and bit later car if you can't notice this.
