Tire pressure

[Mikes92]

Hi all,

Can anyone tell me what PSI I should start letting air out after driving for a long period? I have a Ford F53, 18000 lb chassis with Goodyear 19.5 tires. The manufacturer says 82 cold PSI which they were set at. Today after about 5 hours PSI in the interior rear tire was at 99. Goodyear says 110 is max.

Thanks,

Mike


2015 Pursuit 33BH
New Jersey
Sent from my iPhone using Forest River Forums

[jadatis]

Never let out air when measuring warm pressure of tires

When driving the tires rotate about 10 to 20 times a second , and every rotation , every segment of the tire deflects and flexes back, wich produces heat in the rubber.
this heat is transported also to the tire inside air , which warms it up.
This higher temp in tire gives higher pressure in the tire, you can even calculate it.

Important is that the temp in tire does not get to high.
Normal is when driving about 55m/h , that the temp in tire goes from 65/68 degr F ambiënt temp so inside tire temp cold, to about 110/115 degr F.
With this temp rising the pressure rises about 10/11% , so your 82psi cold would rise under those conditions to 91 psi. So your 99 would indicate a higher temp in tire then 110/115 degr F.

To get lower temp in tire, you need to get higher cold pressure , for instance 90 psi , wich would then rise to 100 psi probably.

I am able to calculate a save pressure for you, so your tire inside wont get to warm, an by that the rubber of tire wont get to warm , so it hardens and damages.

Need to know tire data and best seperate weighed wheel(pair)s.

[waiter21]

NEVER ---

Check the tires when they are cold, more accurately, when you haven't driven in a few hours.

Tire pressure will increase when you are traveling, but will go back down when you are stopped