Fishman, Volvo generally gives two pressures, One for economy and or heavy/max loads (the higher pressure) and one for comfort, genaral use! The 50_ pressure is the max you can put in the tire without it blowing up in your face!!!, minus a safety fudge factor! I would not go above the Volvo max pressure for front/rear because they also take into consideration handling/braking....two important safety factors! Bill