Is the manufacturer's cold tire inflation pressure in regards to a constant value?

[ghostzfh]

The reason why I ask is because tires can gain pressure (psi) when being driven (heat gained from friction which increases internal tire pressure) so I'm not sure what that number exactly entails. Does the manufacturers suggested inflation pressure mean the pressure in the tire should match that value at all times? Tires gain psi when being driven so how is it possible to always be at that exact psi value unless I'm constantly changing the psi in the tires. I'm guessing the number set by the manufacturer is in reference of the minimum value that a cold tire air pressure should be set to. This would mean that slight over inflation is better than under inflation from a practical standpoint. Am I wrong?

[swarb]

Originally Posted by ghostzfh

The reason why I ask is because tires can gain pressure (psi) when being driven (heat gained from friction which increases internal tire pressure) so I'm not sure what that number exactly entails. Does the manufacturers suggested inflation pressure mean the pressure in the tire should match that value at all times? Tires gain psi when being driven so how is it possible to always be at that exact psi value unless I'm constantly changing the psi in the tires. I'm guessing the number set by the manufacturer is in reference of the minimum value that a cold tire air pressure should be set to. This would mean that slight over inflation is better than under inflation from a practical standpoint. Am I wrong?

[new2subaru]

"The tire pressure recommended in your vehicle's owner's manual or tire information placard is the vehicle's recommended cold tire inflation pressure. This means that it should be checked in the morning before you drive more than a few miles, or before rising ambient temperatures or the sun's radiant heat affects it."


https://www.tirerack.com/winter/tech....jsp?techid=73

[Yoshoobaroo]

COLD tire inflation pressure


Sent from my iPhone using Tapatalk

[ghostzfh]

I know it's suggested, but my question mostly revolves around whether or not it is a value that is meant to be held at constant, not whether it is correct or not.

[swarb]

Originally Posted by ghostzfh

I know it's suggested, but my question mostly revolves around whether or not it is a value that is meant to be held at constant, not whether it is correct or not.

No. That value is impossible to keep constant and there are too many variables to affect it. That is why it is suggested...

[ghostzfh]

Originally Posted by swarb

No. That value is impossible to keep constant and there are too many variables to affect it. That is why it is suggested...

So then why do they not reference a range of psi instead of one single psi value? They only indicate that is a "recommendation" or "suggestion" but it's not implied that it is a minimum value, a maximum value, or a constant value.

[swarb]

Originally Posted by ghostzfh

So then why do they not reference a range of psi instead of one single psi value? They only indicate that is a "recommendation" or "suggestion" but it's not implied that it is a minimum value, a maximum value, or a constant value.

Read the tire, there is a maximum value. Mininmum would be how the tire sits given the load.
There are too many variables and too many lawyers/engineers involved to give any definite numbers.

[Twinz]

They know there are a lot of variables that will change air pressure.

They probably use a single cold psi number so that owners won't need a weather station, racing scales, pyrometer, 5 pages of "if/then" instructions, and an abacus to check their tires every time they pump gas.

[RJasonKlein]

Frankly, I'm surprised by your confusion. It's precisely because tire pressure changes with temperature that the manufacturer suggests a cold tire pressure as a fixed reference. Cold means cold. The manufacturer suggests you set the tires to a specific pressure before the the car is driven as a way to eliminate confusion. It's not a minimum pressure. It's not a maximum pressure. It's not a range of pressure. It's not something you need to accommodate for by underinflating in anticipation of increased pressure when hot. Set your tire pressure to the suggested pressure before you drive the car.

That said, the suggested tire pressure may not be what you choose to run depending on your needs, usage, or desire to balance the handling of the car - but that didn't seem to be the source of your confusion.

[Guff]

pv=nrt