Lately, ive seen alot of posts alone the lines of "what psi do I use??". I am going to explain this and give you a little more information as well just to keep in mind.

Tire pressure rating on the sidewall-

The PSI rating on the sidewall of any tire should not be considered the inflation PSI. Ever. Period. This rating does not take into consideration that GVWR (gross vehicle weight rating) for the front/rear at the tires. Again, dont use this to inflate your tires.

So what PSI do I use?-

Alot of people dont realize how easily availible this valuable information is. On most if not all cars, there is a sticker on the drivers side door underneath the latch. There is various information on there, including front/rear tire PSI. There is also this same information in the vehicle owners manual.

The rating that manufactures give takes into consideration that weight of the vehicle at both the front and the rear. The rating they give also gives you the best fuel economy and normal tire wear.

Properly inflating your tires is something that is overlooked by many and is a simple job that can improve mileage, handling, and tire life.

Other things to consider-

Tire pressure is affected by heat. Cold makes the air contract (shrink), less pressure, and heat makes the air expand, more pressure. Your tires create alot of friction when driving (friction is how they give you traction), and friction is released as heat.

A good baseline number is: plus or minus 1 PSI for every plus or minus 10 degrees from what temperature you filled your tire up at.

Another important thing to remember is, always make sure your tires are cool before you inflate them. As I explained before, heat makes air expand and filling a hot tire could make it too low during colder conditions.



An important thing for anyone to remember is, when in doubt, check your owners manual. Your owners manual has tons of useful information for everyday maintenance items.

 

If you really want to get **** about tire inflation, here's something I noticed by checking tire pressures at home.

Parked in the driveway on a sunny day, the sunshine side of the car is a bit warmer. I have set tire pressures like that, then pulled the car into the garage. Hours later, all 4 tires are at the same temperature. Now the sunny-side tires have cooled down and they are maybe 1psi lower than the other side. One psi isn't the end of the world by any means, but it illustrates how this stuff works.

 

Talk about ****! LOL! Great info JimBlake. There is tons of factors that can change tire pressure but the ones I posted are just really basic.

 

Well, it was a test to settle an argument. I said it'll affect the pressure. My wife said I'm being silly. I think we were both correct.