Like Erick says... it's better to re-install the full game... and please if you start it up for the first time with or without Gpx Patch -CALIBRATE MANUALLLY- that's the best thing.
For the tyres... try to put some new BMP's into the game via GP Edit. Tyre outside and Tyre inside but first re-install the game, maybe it's fixed that way.
GOOD LUCK
GPGSL-3: VTR Driver, S4~S11 (2nd,
1st, 2nd, 2nd, 3th, 4th, 3th, 2nd)(Constructorstitel S7 & S9)
GPGSL-4: ONE Racing Driver, S8~S11 // TYRANT Racing Driver, S12:
1st, S13:13th, S14:
1st, S15:13th //
WREXHAM Motorsports Racing Driver S16: ?