Actually TBC doesn't affect physics of player's tires anymore. Only values taken from there is tire width used to draw skidmarks on tarmac afaik.
TGM describes not only construction of tire but its reaction to different forces (read: whole physic of tire). Quasistatic analysis calculates lookup tables for that.
Good luck.
Also, try to update/reinstall latest version of Logitech profiler. I had some issues with old profiler with my G25 when i used it. Then set all values to default (don't remember is there "reset" button) e.g. Force = 100%, springs = 0%, dampers = 0% (rFactor doesn't use springs and damper forces). Turn off centering spring. Then check your controller.ini in userdata: Type=1, Skip=0, Steering effects strength=10000 (ten thousand), Filter not more than 10-15. Also check vehicle specific FFB mult on controller settings screen in rFactor.