Tire inflation
Got E rated tires installed, 80psi max, Tire guy said it would be better to run around 65-70 psi as tires heat up. Always thought I should run max cold rating 80psi. FW weight is around 9000 lbs hooke...
Forum Discussion
@ 06Fargo
If you are reacting to my post before this, then read next topic of mine.
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27477930.cfm
The tire makers determine a maximum load for a sertain pressure ( AT-pressure) so the tire has a sertain deflection, at wich it wont get to warm on sertain area's so the rubber stays flexible, and not harden out and damage at next bendings of it.
European tyre makers even allow 1.4 times the AT pressure cold.
I would not asume that for American tires , because I suspect American tire makers to set a for instance D-load designed tire in the market as E-load , using the reserve to laws of nature. This to fullfill the American Dream of bigger is better.
Once read that tires are tested with 2 to 3 times the At-pressure .
So this makes me conclude that you are allowed to fill higher.
Example : A tire maker designs a tire for D-load use with 65 psi AT-pressure . The absulute pressure the tire can stand even when driving then is between 130 and 185 psi before it blows.
If then the tire maker places it in the market ( with other print on sidewall) for E-load so At pressure of 80 psi, still the pressure wont go over 185 psi ( 3 x 65) when filled cold at freesing temp of water of 32 degr F , and the temperature inside the tire rises to even boiling point of water is 212 degr F. Even not when filled with 1.4 times AT-pressure D and E load.
Worse it would be if the tire maker upgrade it by 2 steps so here F-load with at-pressure of 110 psi.
Again made picture of spreadsheet I used for it, also at bottom the calculation I used for a post back.
If you are reacting to my post before this, then read next topic of mine.
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27477930.cfm
The tire makers determine a maximum load for a sertain pressure ( AT-pressure) so the tire has a sertain deflection, at wich it wont get to warm on sertain area's so the rubber stays flexible, and not harden out and damage at next bendings of it.
European tyre makers even allow 1.4 times the AT pressure cold.
I would not asume that for American tires , because I suspect American tire makers to set a for instance D-load designed tire in the market as E-load , using the reserve to laws of nature. This to fullfill the American Dream of bigger is better.
Once read that tires are tested with 2 to 3 times the At-pressure .
So this makes me conclude that you are allowed to fill higher.
Example : A tire maker designs a tire for D-load use with 65 psi AT-pressure . The absulute pressure the tire can stand even when driving then is between 130 and 185 psi before it blows.
If then the tire maker places it in the market ( with other print on sidewall) for E-load so At pressure of 80 psi, still the pressure wont go over 185 psi ( 3 x 65) when filled cold at freesing temp of water of 32 degr F , and the temperature inside the tire rises to even boiling point of water is 212 degr F. Even not when filled with 1.4 times AT-pressure D and E load.
Worse it would be if the tire maker upgrade it by 2 steps so here F-load with at-pressure of 110 psi.
Again made picture of spreadsheet I used for it, also at bottom the calculation I used for a post back.
