This is what i posted to him:
Warren asked me to help you and here is what you can do.
1. Remove all old logitech drivers, try to do this in safe mode (hit F8 during boot and start in safe mode)
2. Reboot pc and install one of these drivers, depending on the os you use 32 or 64 bit.
Vista 32 bit version:
http://www.logitech.com/pub/techsupport/joystick/lgs501.exe
Vista 64 bit version:
http://www.logitech.com/pub/techsupport/joystick/lgs501_x64.exe
3. Reboot again and be sure the wheel is connected and also powered.
4. Be sure you don't run the Logitech software whlie you use the wheel, i think the logitech gaming software will be run when you boot up the pc so remove them from startup or from registry. If you don't know how to do that just contact me.
5. In control panel game controllers be sure you set no combining axes.
6. Put the all forces slider on 101% and 270 degrees rotation.
The 2 other sliders i have on 0%
7. Enable centerspring but be sure it is set at 0%.
Then go to the controller file, in GTR2 it's the plr file and in race it's a separate controler ini file.
8. Set this value:
FFB Steer Damper Coefficient - "-0.175" [note it is changed to a negetive value]
9. Safe the file and be sure in race you slect the controller profile with the adjusted setting.
Leave FFB on medium or low and try the force feedback.
If you want to tweak FFB settings you can do this in the controller ini files, here are the values you need to adjust to your own feeling to get better steering response:
Basic values
FFB Gain (if I go over .65 on this with my G25 it gets hard to tweak out the center roughness)
FFB steer force max change
FFB steer force output max
FFB steer force exponent (basically works with FFB Gain)
Tire Grip
FFB steer force input max
FFB steer force grip function
FFB steer force grip weight
Stiffness
FFB steer friction coefficient
FFB steer friction saturation
I hope your problem can be solved now and you will enjoy the G25.
I hope it can help him.