Be careful about going over the tires maximum pressure printed on the sidewall. I like 40psi front and rear, it is a bit more stiffer, but gives better mileage, longevity, and accelleration due to less rolling resistance. In the past I would put in about 40 psi and then six months later it would be down to about 32 psi and I would put it back to 40 psi.

It is also said that higher pressure yeilds more load carrying capacity and speed capabilities. I have read that you are supposed to increase pressure a few psi for each 10 mph over 75 mph speed, higher psi - lowers rolling resistance - tires generates less heat.

The downside to high pressure is you use up more brakes. That is why most recommended pressure is about 32psi - 36psi. 32 psi is a good general pressure considering mileage, load, comfort, brake assist, cornering, speed, longevity, and safety cushion where if you misread the pressure guage or the pressure gauge is inaccurate.

Once I had a 2000 lb economy car and had @50 psi and got about 44 mpg. But since I almost blew up a tire hitting a pot hole, and rear brakes got about 25,000 miles, I don't put that much in anymore.

Even though compact spare tires are supposed to have 60 psi, but I get scared to put more than 50, it bulges so much.