Tire pressure before going south
I am curious what others do about air pressure in your fifth-wheel tires. If you set it at proper PSI in the north at 30 degrees and then end up in FL at 90 degrees, what effect will that have on the ...
Forum Discussion
Mind there are 2 reasons for tirepressure advice.
1 is for handling, traction and durability and fuel-saving.
2 is for savety of tire so it wont get overheated and damaged by that .
For reason 1 you should keep the cold pressure at the adviced or calculated pressure at the ambiënt temperature.
So then compensate for pressure dropping or rising by temperature dropping or rising. then use the rules of tumb , but I also made a spreadsheet for it.
The rule of tumb only goes for tires filled up to 45 psi , if its filled to 80 psi it will rise or dropp more. Better then would be to go from a sertain percentage of the cold filled pressure .
For savety of the tire the story is different, and I already explained that in my first reaction in this topic.
But in short , heating up and cooling down of tire takes care that no spot of the rubber reaches a sertain temperature that it hardens and crackes in next bendings.
When Ambiënt temp is lower more temp difference in and outside so cooling down is more so heating up can also be a bit more.
So the lower pressure so more deflection gives a bit more heatproduction but also better cooling down because of more temp-difference between in and outside tire.
so for reason 2 you dont have to fill up to calculated or adviced pressure when temp drops.
If you take care to have enaugh reserve in the pressure dont worry about ambiënt temperature dropping or rising and the pressure dropping or rising that goes with it.
Simple defenition of cold pressure is when inside tire temperature = outside tire temperature.
And thats not the case for instance when sun on the black tire.
1 is for handling, traction and durability and fuel-saving.
2 is for savety of tire so it wont get overheated and damaged by that .
For reason 1 you should keep the cold pressure at the adviced or calculated pressure at the ambiënt temperature.
So then compensate for pressure dropping or rising by temperature dropping or rising. then use the rules of tumb , but I also made a spreadsheet for it.
The rule of tumb only goes for tires filled up to 45 psi , if its filled to 80 psi it will rise or dropp more. Better then would be to go from a sertain percentage of the cold filled pressure .
For savety of the tire the story is different, and I already explained that in my first reaction in this topic.
But in short , heating up and cooling down of tire takes care that no spot of the rubber reaches a sertain temperature that it hardens and crackes in next bendings.
When Ambiënt temp is lower more temp difference in and outside so cooling down is more so heating up can also be a bit more.
So the lower pressure so more deflection gives a bit more heatproduction but also better cooling down because of more temp-difference between in and outside tire.
so for reason 2 you dont have to fill up to calculated or adviced pressure when temp drops.
If you take care to have enaugh reserve in the pressure dont worry about ambiënt temperature dropping or rising and the pressure dropping or rising that goes with it.
Simple defenition of cold pressure is when inside tire temperature = outside tire temperature.
And thats not the case for instance when sun on the black tire.
