The simple answer is friction. Spinning tires are coming into contact with the road. The road's surface is not perfectly smooth -- it has a certain amount of roughness so the tires can grip and propel the car forward.
Any time you have friction between two surfaces, and one of those surfaces moves to overcome that friction, a certain amount of energy from the process is lost as heat.
the friction between the tire & the surface your driving on causes heat and which heats the tire + the air...
ONLY the front tires can spend on a non-all wheel front end driven car.
Friction
Because heat is created and it changes the air pressure
Because it experiences large anounts of friction every time the car is driven
The tire will go flat.
Cold is what the pressure listed is for. This is usually hard when having driven the car that day so when they are hot just subtract 3-5 psi. Being + or - 3 or 4 psi will have negligible "real world" effect.
Tires create friction, which in turn creates heat. Heated objects expand.
Tires of car get hot at driving time because the wheels are flex repeatedly as the rotate. The tire deforms at the road surface and compresses and the other reason of hot is the lack of air pressure causes greater deflection, and more movement in the rubber
Heat is built up while driving and that will increase pressure in the tires.
Cold tires is just a term used to describe a tire that has not been driven lately. Driving the car creates heat in the tire thus increasing the air pressure. That is why you should always check the air pressure when the tire is cold or has not been driven for a few hours.
In a hot climate air expands, causing more pressure, not less. If your tires are continually losing pressure you have a leak that needs to be fixed.