Tire Pressure Help

[DonTX]

It looks like we will head out for a two month cruise or so with my new to me 35ft fifth wheel RV.

The trailer will weigh around 13K I guess, and it will be a ways until I can get to a scale to see just how this weight is distributed. What I would like is someone with this type rig to give me some ball park figures on initial truck tire pressures. I can adjust later when I find a good scale.

 

[B.G. Smith]

The loaded recommended air pressures should be on you door post. I would start out with 70 in the front and 65 in the rears. bg

 

[Jgolden]

Don,

You might also read the fine print on the side of the tire. Load range may or may not be the same as the original ones. Check the date code while your there.

Most tire companies have pretty complete info on a web site.

 

[JFaughn]

Thats with stock tires , once you change tires you only go by what is on the tires , I would just adjust for ride comfort by 10 % .

 

[MAllen1]

I would go with what is written on the tire. Reason is because of 2 reasons/examples 1)The firestone/ford explorer problem was because ford stated in the door to inflate to 26 psi and the firestone tire stated to inflate to 35 psi (you do the math) 2)you may or may not have a different size than stock and the recomendations that dodge gives you, witch may or may not be as good as ford, would not be good for a bigger wheel/tire combination.

 

[Grizzly]

Since you have dual wheels and you don't have that much pin weight, (say 1800 lbs), I'd use 55 psi on the rear tires and 65 psi on the front depending on your load range. I also support going with what is said on the tires than what is said on the door jamb. Don't forget to inflate the spare the same as the highest psi level of the other tires.



Have a great trip Don. Give me a ring when coming through Albuquerque.

 

[DonTX]

Thanks Grizzly, if I ever get out of here in time, will sure look you up coming thru Albuquerque. I am almost on the line to saying to hell with it and just go next year.

I don't have a loading pressures chart on my door, must have been some other years, that is a pretty large chart to put on a door anyway. I am quite aware of MAX pressure for MAX loading, but that creates an overinflation situation unless you are loaded to the maximum, which I sure hope I am not. Pressure must be adjusted to match the load, as each tire manufacturers chart will indicate. My problem is that I don't know yet what the weight on each tire is, so need a starting point until I can get to a scale and get accurate axle weight.

I am getting the idea that many of you are just inflating to the max on the sidewall and saying to hell with what is correct. That is not good, pressure must be correct for the load on the tire according to the manufacturer of the tires.

 

[Jgolden]

Max pressure is for max load but I don't see how having less weight could be a problem. The main effect is on ride comfort. That's a pretty big trailer.

As in everything, you need to do what makes you comfortable. Put me down as a guy who is always at max inflation on all tires.

Take the trip.

Post on the TDR towing form and see what info you find.



PS,

I'm heading west soon, I'll wave.

 

[DonTX]

Hey, we should cross paths somewhere, honk if you see a green dually with a Mercedes grille! I am going north to the Canada border, then west to Montana, down thru NV etc and back home if I don't get lost.

I used to do the same thing on pressures, but a little reading on tire makers sites made me stop that. They call that overinflation, and claim it is as bad as underinflation. My tires are old, I need to do the right thing if they are going to last me this trip.

I did transfer this over to the Towing, it was a goof on my part that it ended up here even. I'm old, I tend to do things like that sometime.

Max pressure is for max load but I don't see how having less weight could be a problem. The main effect is on ride comfort. That's a pretty big trailer.

As in everything, you need to do what makes you comfortable. Put me down as a guy who is always at max inflation on all tires.

Take the trip.

Post on the TDR towing form and see what info you find.



PS,

I'm heading west soon, I'll wave.

 

[dpuckett]

I dont think you'll have any problems with inflating to the recommended max pressure for max load. I've done that many times, and been just fine. For towing 13K, and assuming you'd have a tongue weight of more like 2K, I'd start out at 70psi for L. R. E tires; 60 for L. R. D tires, and see how hot they get, at least til you can get to a scale. If you are over 1500 on your pin weight, leave them be. If you're under 1500, split the difference between the max and your "normal" empty pressure. (i. e. if you normally run at 50psi for comfort and empty wear, max is 80, inflate to 65). That is based on nothing scientific, other than my personal observations and experience.



Keep in mind that you (hopefully) wont be running this pressure for the life of the tire, and it wont make much difference in the grand scheme of the tire life if you're overinflated for a few thousand miles.



When I tow, I normally bring the pressure up to 80psi, hook the gooseneck on, and sometimes have to put a bale on the bed in front of the g-n hitch. Overloads are normally hitting their stops plus an inch or two.



Daniel