Your Potenza 225x35x18 S-03's were designed to run on 8" wheels in order to not distort the tread surface.. even thought the chart on TireRack shows that a 7.5" rim is the MINIMUM allowable for that size tire.. I and a friend had simular damage caused by running two different brands on undersized front wheel rims of Cougars.. The lateral stress placed on the tire by the front wheel drive, and distortion caused by the small rim distorts the tire surface causing heat build up which can even cause a tread/belt seperation.. best bet, change the wheel width or change the tire size.. I now run 215x45x17 S-03's on the front of my Cougar.. and sometimes 225x40x18 S-02's..