I run 18/ 28, but my car has been loose for 3 years, it would just lite up the tires I could never get it just the way I like it. Then put on the new tires, that have more grip, and BAM the car is right ot I had to free it up. Now with that being said I have heard guys running very high PSI to make up for the sidewall flex in the new tire. This will mak the new tire ack more like the BFGs. So, if you have good set up that you like with the BFGs then you may want to try plus 10 psi per wheel.