Originally Posted by MMMMM3
It has a much stiffer side wall with a 101 load rating in the 265/40 18 size compared with a 97 load rating in the ps2. Should be able to fix the problem by putting the pressure down to 30-31psi instead of the recommended 35psi for the ps2 in the rear (18 inch) tires.
See table to work out the pressures for your size tires and for different load rated tires:
Thanks for the info. This makes sense. I will try lowering pressures.