Quote:
Originally Posted by MrGallegos
... it seems what is needed is a table to determine what PSI to use based on the load, such as one for traveling with the trailer completely empty, such as taking it for repairs and one for a fully loaded camping trip.
|
I wouldn't try to get too picky or too exact about tire pressure. Trying to tweak it would be a wasted effort. After all, the tire will heat up considerably as you drive, which means the pressure will change by several psi, sometimes by many psi. The amount of heating, and therefore the amount of pressure change, will depend on whether it is a hot day or a cool day, whether you are driving on asphalt (black) or concrete (light color) and even which tire is on the sunny side of the trailer and which is on the shady side. All of these things are out of your control, so trying compensate for them is not possible, and not needed.
These are a few rules of thumb for tire pressure.
1. Under-pressure is VERY destructive to tires, and almost guarantees a failure. Over-pressure may result in a bit more tread wear in the center, but is otherwise harmless unless you air them up way beyond the sidewall rating.
2. Air up your tires first thing in the morning, before any heating has occurred, and then
leave them alone! Do not let air out of a tire to reduce the pressure caused by heating. The tire designers have taken this heating into account as part of the design.
3. Fourteen inch trailer tires (load range C) are almost always rated for 50 psi max pressure and 1870 pounds weight max at 50 psi. On a TM, they don't have much margin, so
always air them up to 50 psi.
4. Fifteen inch tires may be load range D (65 psi max) or load range E (80 psi max). As Dave said, you would probably want to run both kinds at 60 psi (TM lightly loaded) or 65 psi (heavily loaded). Stay within that range.
FWIW, I finally broke down and got a TPMS a year ago, and watched the readings. I was surprised to see that when I started the day at 63 psi, the pressure quickly rose to 68-70 psi, and sometimes maxed out the reporting capability of the TPMS (72 psi) on a hot day with a loaded TM. I also saw that the difference sunny-side to shady-side was usually 3 or 4 psi on a sunny day.
Bottom line. Choose an initial pressure for the kind of run you expect to make that day. Air up the tires to that number, and leave them alone. If you don't want to spring for a TPMS, get a simple tire pressure gauge, and check them a couple times during the day. At every stop, I make it a practice to put my hand on the sidewall of the tire and feel for badly increased temperature, a sign of under-inflation that should be dealt with promptly.
Sorry such a long post, but after a lot of experience (good and bad), and a lot of actions (smart and stupid), it seems to work. It won't make things perfect, but it will help.
Bill