Tires: inflation pressure of tires, tire placard, inflation pressure

Question
QUESTION: For better wear and mpg is it advisable to set the tire pressure at the psi on the sidewall of the tire?

ANSWER: Jeffrey,

On every vehicle sold in the US - and I understand this is a worldwide practice as well - there is a sticker – commonly called the tire placard - that lists the original tire size and the proper pressure for that size.  The placard is usually located on a doorpost or in the glove box – but sometimes it is located in the trunk or on the fuel filler door.

Personally, I like a car that handles crisply. So I use 3 to 5 psi above the placard pressure.  I also get better fuel economy, better wet traction, better snow traction, better tire durability, better tire wear, but I do have a degradation in ride harshness (but I am willing to put up with it.)

BTW, it doesn't matter who makes the tire or what pressure is listed on the tire's sidewall, if the tire size is the same as the placard, then the pressure listed on placard is also appropriate.

But, no, Max Sidewall pressure is exactly that - the maximum that should be used, not a recommendation.

---------- FOLLOW-UP ----------

QUESTION: By inflating and running the tires to maximum psi per listing on the sidewall as opposed to marking up the psi on the placard a little bit as you do, will I still get "better fuel economy,better wet traction,better snow traction,better tire durability and better wear" as you suggested above? I know the ride will will be more sensitive to the vagarities in the road.I will thank you in advance for your reply and your time.

Answer
Jeffery,

I have had long and acromonious discussions concerning what happens when you go beyond 3 to 5 psi above the placard.    There is a lot of contradictory information in that region - mostly because everyone wants to report the info in terms of the max tire pressure, instead of referencing the placard pressure.

My opinion is that going beyond this 3 to 5 psi recommendation is unknown territory, and there are some indications that there may be some hidden dangers - so I don't recommend and, in fact, advise against it.

If you read my web site, I think can see where I am getting this.

http://www.barrystiretech.com/

Pay particular to "Load Tables" and see where the max sidewall pressure comes from.