I just had this discussion with a tire dealer when I put new tires on my pick up. Max pressure is around 80#. I run the tires at 65#. The door sticker says to run 55# front and 80 rear. When the previous owner did this he put new tires on at 20K miles. Why would you want less pressure on the tires that have the weight of a diesel engine on them and max pressure on the rear tires with no load on them. I put 35K on my tires keeping them rotated and equal pressure. They are still in great shape. Not trying to argue but it goes against what I was taught in school and the tire dealer agrees with me. The only reason I put new tires on is because I bought new rims for the vehicle. BTW after fighting GM on tire wear issues on our 07 Impala, the service department and alignment shop both advise against the recommended 32# on the door. They both said to inflate to max pressure since the rear has the highway patrol car suspension package now. It has not affected the TPMS yet. Again I am not trying to start an argument.