In most cars there is a tag alongside the drivers door indicating relevant information including recommended tire size to use and tire pressure to apply. My question is: Assuming that the car owner will need new tires periodically using different brands but the same size, does the recommended car manufacturer tire pressure still apply or does it necessarily have to change. Every time I get my tires balanced and rotated, the mechanic always overpressurize the tires by about 5 psi although I suggested to them to follow the pressure listed on the tag.
Tire pressure recommendation changes with size, not with brand or model of tire. The air in the tire supports the weight of the vehicle. A tire is, if you will, just a very fancy air container. Different sizes of tire have different volumes of air they can contain and this influences how much inflation pressure is required to support a given load. So as long as the tire size does not change, you use the information on the Tire Load and Information Placard on the car. If your mechanic is not inflating the tires properly it is time to find a new one. What else is s/he doing wrong?
The answer has been provided. However, I wish to expand that you need to use Google Search to find credible and accredited automobile sources of information for there is loads of information as to tires that most people have no idea exist. For one, there is more than one recommended cold air PSI recommended by car manufacturers. It deals with the weight or payload the car deals with. For one person in an daily commute to/from work, there is a recommended cold temperature PSI. That same car going a road trip with more people and luggage, more payload, needs a higher PSI to handle the temperatures generated by the speed and to handle to increased weight. Tire temperature can reach 200 degrees F in normal driving. This means that in a cold morning with cold tire temperatures the grip capacity of the tires is reduced. By not knowing this, people take chances as to speed, following distances, speed in turns, etc. and end up spinning out or crashing due to under or over steering. There is also the issue of kinetic energy. Very complex subject that by being ignored causes millions and millions of car crashes per year. This is my best answer.
Yes, stick with the recommended PSI which the automaker of you vehicle determined would be best. This would be true regardless of the brand and model of tire, recommended tire PSI is based on the vehicle. And yes, some tire retailers can be a bit sloppy with putting the proper PSI in tires. Don't trust them, always double check. A pound or two over is fine, but anything more will unnecessarily make your ride more harsh and potentially wear your tires prematurely.
