I just put on some 235/45R17 Bridgestone Fuzion ZR1 with a 94 load rating. What psi should I use? The 215/50R17 I kept at 32 psi according to the door jam. I had Bridgestone fax me a load and inflation table and it shows at 32 psi for the 215/50's the load rating was 1224 lbs. To match the same load rating I would run 29 psi in the Fuzion's which would be 1235 lbs. Is this how you determine what psi to run?

 

It being a slightly stiffer tire, I'd start a little under the factory pressure of 32 (29-30) and then adjust a few pounds up or down to get the handling and ride you want. Don't worry about the load unless you are planning to haul a load of bricks in the car.