Tire pressure

[Russ40]

Bought EEZRV TPMS system for my fifth wheel. Saved me before I left the driveway. Lol ( another story). Checked tires before I left. 80 psi. Cold. Tires are Westlake 235 80r 16 load range L.

Question? How much pressure increase are you seeing on your tires. My numbers running down the highway at 65

Left sides:

95 psi 93*F
93 psi 93*F

Right sides:

87 psi 93*F
90 psi 92*F

I didn't think the tire pressure would go up 15 psi. Left side of trailer has a full size fridge.

[jadatis]

One of two is not acurate given , or your starting cold pressure was no 80 psi for all tires.

The pressure rising is related to the inside tire temperature, I even made tabels for that.
So its never possible that if you filled for instance at 65 degr F ambiënt temp a cold pressure of 80 psi exactly the same for all 4 tires, that at 93 degr F it gives different pressures.
My idea is that the temperature indication is off, most aftermarket TMPS are screwed on the valves, and so measure a temp somewhere between inside and outside tire .
The pressure measurement can be off a bit , but then for all sensors the same .
So to compare the pressure reading is better to use.

In spreadsheet I made, you can fill in cold pressure , and cold temp , and warm pressure to see what the inside tire temp then is.

Did that for your data. asumed cold pressure measured at 65 degr F
Cold pressure is when inside tire temp= outside tire temp, that simple.

Left sides:

95 psi 93*F ?LFr 148 degr F. this must be when this tire has highes weight
93 psi 93*F ?LRr 137 degr F. so this one second hw

Right sides:

87 psi 93*F ? R Fr 104 degr F. this one lowest weight
90 psi 92*F ? R Rr 120 degr F. is 3th in line H/L

Once determined that when driving 55m/h and 65 degr F outside , the insidede tire temp rises to about 110/115 degr F.
So you driving 65m/h would risise then inside tire temp more..

So yudge yourselfes if these tmps are alright.
My idea is to highen up the cold pressure, so hottest tire get lower inside tire temp.
Your L loadrange are allowed 130 psi , or you read the speedcode L , wich is maximum speed of 120km/75m/h.

Did you also notice that the weight-division is crossed between the axles.
You almost always see that whenn weighed.
That is , when you gave the measurements as I think and put ? in front.

Greatings from a "Dutch pigheaded Selfdeclared tirepressure-specialist""
Peter

[Russ40]

Pete
Thanks for the reply.

I am using the valve stem screw on pressure and temp monitoring. I will search the site for your chart. The data would be awesome to see.

When I checked the tires they had been sitting for a couple days. Not sure if the exact tire temp but outside temp was 78 deg.

As I was watching as we drove down the road. I expected tire temp to raise more than it did. Did not expect the tire pressure to raise as fast.

Will look at your charts.

Thanks again

[jadatis]

Added an image I made with the spreadsheet.
But will give link to my one-drives public map , that belongs to my hotmail.com adress with same username as in this forum ( so jadatis, like this to prefent spamm).

https://onedrive.live.com/?id=A526E0...26E0EEE092E6DC

You can navigate that and the submaps, many about tirepressure, and many in English, but also Dutch , I live and was born in Holland.
This picture is in the submap "all about tirepressure/Examples, together with others , also in kPa and both degr F and C .
The spreadsheet I did not put in there yet, so you cant make your own list.
But give the range you want in pressure and temperature, and I will make one.

But if you measured 80 psi at 78 degr F the temperature rising would even be more The lowest 87 psi then would mean an inside tire temp of 118 degr F , istead of 104 degr F. the highest 95 psi then would be 163 degr F instead of the 148 I first calculated for the 65 degr at 80 psi.

EDIT: uploaded the psichanchefortemp-spreadsheet, so you can play with it yourselfes.
I dont know if you are a little bit handy with Excell ( or CALC) , but mind that its not protected, so if you fill something in a cell with formula's , you overwrite them.
So if you store it on your computer, always save the original and give a new one a new name, so you can always go back to the original.
At the top the pressure calculation for tires with still the official European calculation.
Second the pressure/temperature playing part, with at the bottom the part I used here, for determining temperature.
below that I placed 2 charts, in wich the fatt printed pressures can be chanched to your needs, also the row in front with temperature you can chanche to your needs.
But dont touch the other cells, they contain formula's .
Best is to download it to your computer, because excell like programs in the claud , cant handle dropdownbars I used in the first part for loadindex/kg/lbs.
For other spreadsheets on my drive, also sheetprotection is used, to prefent you from overwriting formula's, and those cant also be handled by excel in the claud.