Standard air pressure in your car's tires may vary from what the manufacturer of your car and what the tire manufacturer say. You want to know both specifications when maintaining your tires.
To find the air pressure specification on a tire, look at its sidewall. The information is found circled and would usually read what the maximum pounds per inch (PSI) pressure limit is for the tire. This is a maximum and often differs from the vehicle manufacturer's specifications.
Your car would usually have the tire's standard air pressure in one of two places: in your owner's manual and/or on a placard or sticker, affixed on the driver door or the center console. Your car's tires should be inflated by these specs. These specs factor in the exact weight of your particular car and other calculations that go into tire pressure specifications (i.e. inertia).
The spare tire that comes in your car would likely be a space-saving tire. This is smaller than a normal tire. To continue giving you proper handling of your car, it is designed to hold up similarly to a normal tire. Its air pressure specification will likely be higher than the other tires--around 60 PSI.
