you NEVER inflate the tire to the max PSI

As you drive and the tires warm up the air in the tire expands, THAT'S your max PSI. If you just inflated it to the max and then drove on it and the air expanded you are looking at blowing out your tires.

You look on your door jam if anything and that will tell you (if you still have the factory size tires) what the recommended PSI range should be.

 

X2 ^^^

The PSI on the side wall is the MAX PSI for the tire, you NEVER EVER want to be at the MAX PSI.

 

why do all the shops inflate to max?? and whenever you inflate a tire the air is hot anyway from the compressor so its going to deflate when its not being driven then it will warm up when your driving and be back at max.

 

I don't know what shops you are going to, but i've never had a shop inflate my tires to the max, and if I did, i'd stop going there. Most shops shoot for 30-35 PSI for most passenger cars.

As a general rule of thumb, shops really are not good at inflating tire to the recommended PSI, nor do they usually set all 4 tire to the same PSI. This is why I ALWAYS check my tires after it goes to a shop and adjust to the proper PSI listed on the door (I actually go with 32 PSI instead of 30, but close enough)

The air that comes out of an air compressor is not near as warm as it gets when its in your tires after driving on them for a while. Especially in the heat of the summer.

You will notice when you check the sticker in your door jam that it says inflate to 30 PSI (cold PSI) This means it should be around 30 PSI while the tire itself is cold.

Inflating to the max PSI on the side of the tire is not only putting you at risk of blowing a tire, but it is making your tires wear unevenly, and your car not handle as well as it should.

 

Wow, have you ever read your owners manual? I'm sure it does not say to fill all tires to the max.

The max psi rating is put on there so you know what value never to exceed- the tire manufacturer has no clue what kind of vehicle the tire is going on other than car/truck- but its just as likely to be used on a light car as on a heavier car. So it is up to the manufacturer to determine the proper inflation pressure given the weight of the vehicle given the tire size used. What is the correct pressure for one car could be over or under on another vehicle with a different weight.

You want it so that when the car is normally driving, the tread area is flat with the road. Under inflate it, and only the sides will touch- over inflate it, and only the center will touch- and the tires will wear out unevenly, and the car will handle poorly.

No shop inflates tires to the max. If someone does that to you at a tire/repair shop- find the owner and let them know (because their tech is probably doing that to everybody, and few people double check).

Air sitting in a compressor's tank is not hot- it is room temperature if it has been sitting awhile. I could see it being hotter if the place was using a ton of air and running the tank low- so you were getting air almost straight out of the compressor into the tire- but thats generally not the case. Realistically though, if you're airing up with your home compressor- the compressed air has cooled to room temperature sitting in the tank for hours.

If you really were that worried about slightly warmer air throwing off your 'cold' numbers- then inflate them to the recommended pressure- and recheck them the next morning.