# Myths and Facts



## Discount Tire (Jun 12, 2012)

Myth or Fact: The pressure listed on the tire sidewall indicates the recommended pressure?

Myth or Fact: Tire pressure does not need to be regularly checked for vehicles equipped with TPMS?

When it comes to tires, there is a lot of misinformation out there. Check out our write-up linked below where we dismiss some of the common myths surrounding tires and tire safety. 



*Myths About Tires and Tire Safety | Discount Tire*


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## obermd (Mar 3, 2012)

For the first "myth" about the tire pressure.

Yes, this pressure is the maximum cold pressure for the tire. However, as you drive the tire will heat up and the pressure will increase. This is ok - just don't inflate cold past this point.

Tire load ratings are set assuming the tire is set to the sidewall pressure. As you reduce the tire pressure you reduce the load rating for the tire. This was the underlying problem with the 2002 Ford Explorer tire blowout/rollover debacle. Ford's recommended tire pressure was so low that when Firestone investigated they declared the tires to be unsafe at that pressure with four adults in the vehicle.


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## Discount Tire (Jun 12, 2012)

You're exactly right, obermd - tires are pneumatic and load carrying capacity changes with pressure. 

You're also right in saying that tire pressure fluctuates with temperature and while under operation; this is known as "hot" pressure and is to be expected. "Cold" is defined as in the morning before the day's ambient temperature, sun's radiant heat or the heat generated while under operation causing the tire pressure to temporarily increase, or become "hot". 

The recommended pressure for the vehicle is determined from the original equipment tires and pressure indicated on the vehicles pressure placard and is rarely the max the tire is capable of. Running a tire a near max inflation could cause irregular wear. If running a different tire than what came factory, the pressure recommendation may change depending on the tires construction and load index.


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## Rivergoer (Mar 30, 2017)

Tire pressure also has a significant impact on fuel economy.

Running tires just 5 psi under-inflated drops my diesel by up to 3-4 mpg. Max cold pressure on the sidewall is 44 psi (General Altimax RT43)


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## MP81 (Jul 20, 2015)

Rivergoer said:


> Tire pressure also has a significant impact on fuel economy.
> 
> Running tires just 5 psi under-inflated drops my diesel by up to 3-4 mpg. Max cold pressure on the sidewall is 44 psi (General Altimax RT43)


Yup, I run our Fuel Maxes at 46.5 psi (well, when I install/rotate them. I usually forget to check in between). I think max is 51.


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