Ok , sorry , I guess I started on the wrong person. The fools running at max pressure on the tires sidewall don't know what they're talking about. The bikes tire pressure is determined by weight. That's why you get separate pressures front and rear and with or without passenger. As far as the truck tires , did you ever wonder how 30 pounds of air holds up 4,000 pounds of truck? The weight is spread by the volume of the tire. No , your larger tires do not require more pressure.