Checking and filling tires

[SHRED]

I've always wondered this.

I get checking the tire pressure when cold.
Here's the question:
Say they are 5 pounds underinflated when cold could I add 5 pounds even after they are warm and still be accurate?

[beachbum bob]

1. acurate in what way?

if tires are spec's at 30psi "cold", obviously cold is a relative term,

[SHRED]

2. Accurate I the sense of...

...if I put the 5 pounds needed after they are driven on and warned up will they indicate the proper pressure when they return to cold status.

[MichMan]

3. You would have to know the rate of expansion between hot and cold

Since the extra 5 pounds you are adding is already cold, it would still only be 5 pounds more when cold. When hot it would be higher than 5 pounds by some expansion factor depending on moisture content

[bluedigger]

4. This has been studied extensively in New England.

No consensus has been reached, although the conclusions seem to be regionally biased.

[CentralMass]

7. :-)

[CentralMass]

5. Tire tires lose or gain 1-2 pounds per square inch (PSI) for every 10℉ change in temperature7

However your question is tricky. When you say warm do you mean the ambient air temp or warm as in you driven the car prior to inflating them.
Below is a link to a really good article on the subject.





https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=73

[SHRED]

8. As in driven to a place to fill with air.

[c-rational]

9. Thanks - good article and info.

[sprinkleeninow]

6. I always give my tires a tad more than indicated.

When I followed the recommended number, I would re-do them with a bit more bc of the 'ride'. I also do a visual to ascertain how they look. Right now I need AIT. Air in tires! ☺

[EX500rider]

10. The big thing is to use the right pressure...not the "max pressure" listed on the tire...

....the PSI you want to run is written on the inside of your drivers door or in your owners manual.....running the "max pressure" written on the tire is a mistake many make, that is only for if you car puts the max X lbs on the tire that the tire indicates.
Tires can go on many cars both light and heavy, the tire manufacture has no idea what you are putting it on, always go by the car manufactures recommended pressure.