Tire pressure
Tires inflated to the maximum pressure stated on side wall , how much will that pressure increase from the heat of the road ? for you folks that have tire monitors , Thanks
Forum Discussion
OK then the pressure rising by temperature rising of your 5th wheeler tires is from 50degr/80psi to 109degr/91psi and 115degr/92psi. This all determined with my spreadsheet as tool.
this only courced by the about 10 to 15 times a second deflecting and flexing back of everey segment of the tire-sidewall and a bit heatening the treath by the resistence treath/road.So no extra heating by braking.
this is a heatening up of between 59 and 65 degr , while it should be only 47 degrees, as far as I concluded.
Now I state that the temperature rising goes linear with the deflection of the tire, and I found a relation between the deflection and the surface on the ground, if surface gets 2times as small the deflection gets 2*2 times so 4 times as small so quadratical.
These ST tires have more loadcapacity mainly because for lower speed of 65m/h there is more deflection allowed, wich will give more heat-production, if you drive the same speed. So I state 2 times as much deflection gives 2 times as much degrees temperature rising. All verry discussable I know.
Now in other topics I already found proove that for ST tires also 10 psi extra above the pressure written on sidewall is allowed by TRA.
It is adviced for higher speed then 65m/h, but now we use it for lower temperature.
So I calculated what would happen when you would put your tires at a cold pressure of 90 psi instead of 80 psi wich I asume is written on your tires so they are E load/10PR tires .
You must be carefull with that , because if your tires are already damaged by to much deflection , wich I expect because of the temperature rising, they will still blow-up soon and you will blame it to the high pressure. But if you only have then for a 1000 miles under the 5th wheeler you can do it to my opinion. When the tires are new and so not damaged, the 90 psi is sertainly ok.
When cold pressure 90 psi its 90/80 times the old pressure, and so the surface on the ground is 80/90 times the old surface.
square(80/90)=0,79 x deflection old so temperature chanche old
So 59 degrees gets 46,61 degrees
And 65degrees old gets 51.35 degrees higher temperature warm then cold what the temperatures will get in the new situation.
This is still somewhat high but about that 47 degrees I determined to be ok.
Then I filled this in in my spreadsheet and made a picture of it. fooled the programm a little to get all the temperatures in one picture, so swiched warm and cold .
Then the 90 psi cold filled will rise to between 99.6 and 100.5 psi when driving. To my opinion then we give the tires a deflection a LT tire would have gotten and so saver for the tires.
If you do this filling your tires to 90 psi,you would measure about these warm pressures and temperatures, and if so it prooves that the temperature rising is linear to the deflection and the deflection is quadratical to the surface on the ground.
But do you also have TPMS on the tow-vehicle you tow the 5th wheeler with. Because there the pressure are determined for LT tires the temperature rising and so pressure -rising should be lower.
Would be a good comparison.
this only courced by the about 10 to 15 times a second deflecting and flexing back of everey segment of the tire-sidewall and a bit heatening the treath by the resistence treath/road.So no extra heating by braking.
this is a heatening up of between 59 and 65 degr , while it should be only 47 degrees, as far as I concluded.
Now I state that the temperature rising goes linear with the deflection of the tire, and I found a relation between the deflection and the surface on the ground, if surface gets 2times as small the deflection gets 2*2 times so 4 times as small so quadratical.
These ST tires have more loadcapacity mainly because for lower speed of 65m/h there is more deflection allowed, wich will give more heat-production, if you drive the same speed. So I state 2 times as much deflection gives 2 times as much degrees temperature rising. All verry discussable I know.
Now in other topics I already found proove that for ST tires also 10 psi extra above the pressure written on sidewall is allowed by TRA.
It is adviced for higher speed then 65m/h, but now we use it for lower temperature.
So I calculated what would happen when you would put your tires at a cold pressure of 90 psi instead of 80 psi wich I asume is written on your tires so they are E load/10PR tires .
You must be carefull with that , because if your tires are already damaged by to much deflection , wich I expect because of the temperature rising, they will still blow-up soon and you will blame it to the high pressure. But if you only have then for a 1000 miles under the 5th wheeler you can do it to my opinion. When the tires are new and so not damaged, the 90 psi is sertainly ok.
When cold pressure 90 psi its 90/80 times the old pressure, and so the surface on the ground is 80/90 times the old surface.
square(80/90)=0,79 x deflection old so temperature chanche old
So 59 degrees gets 46,61 degrees
And 65degrees old gets 51.35 degrees higher temperature warm then cold what the temperatures will get in the new situation.
This is still somewhat high but about that 47 degrees I determined to be ok.
Then I filled this in in my spreadsheet and made a picture of it. fooled the programm a little to get all the temperatures in one picture, so swiched warm and cold .
Then the 90 psi cold filled will rise to between 99.6 and 100.5 psi when driving. To my opinion then we give the tires a deflection a LT tire would have gotten and so saver for the tires.
If you do this filling your tires to 90 psi,you would measure about these warm pressures and temperatures, and if so it prooves that the temperature rising is linear to the deflection and the deflection is quadratical to the surface on the ground.
But do you also have TPMS on the tow-vehicle you tow the 5th wheeler with. Because there the pressure are determined for LT tires the temperature rising and so pressure -rising should be lower.
Would be a good comparison.
