Tire pressure increase to save fuel - safe ?

Are these stock tires or custom or low profile tires also re check your manuel 30 psi for the front seems odd that low of a presssure would cause excessive tire ware on the front===most compact and full size cars use 35 on all four the only time i used 55psi was for a pickup i used commercialy ===sub compacts with the smaller tires i am not familar with

The car is a 1999 Mercedes SLK 230 and has low profile tires. The reason that the front tires take less air pressure is that they are just a bit smaller. I figured the recommended tire pressure was for handling.

Make a point to realize that the recomended pressure is a fine tune engineered aspect of overall tire life/traction/and mileage. Over inflating above the manufactures reccomended pressue will decrease the "footprint" of the tire to the pavement. This will cause abnormal wear and have less traction in water and in turning. For optimum tire life AND mileage, you need to adapt the pressure to the type of trip you are about to take. If for instance you were to take a non stop interstate trip at speeds of 65+ additional inflation makes sense. If you prematurely wareout your tirea, the savings in fuel will be recycled into the $400 to replace the tires.