Tire pressure

[DavidH2]

If you have a tag, their scale has 3 sections. As long as I stop my Entegra 45 ft ciach with toll window opposite the operator panel. The tag will be in section 3. This gives me AXLE WEIGHTS for each one. Not quite as good as individual wheel weight but it is plenty accurate for using the chart.

[tropical36]

Originally Posted by rayfannin

I have a 2007 Newmar Essex 45' tandem axle class A. It has 315/80R22.5 Michelins all the way around it. Could someone please tell me what the recommended tire pressure should be for them?

Thanks,
Ray

Have each axle weighed at any interstate truck stop and have always found them glad to help out.
Then for using the inflation chart for airing them up about 10% over the recommended PSI, for taking care of all the variables.
Without the weigh in, you're pretty much in the dark, but when all else fails, do so for each axle's weight rating posted somewhere in the coach.
You'll see a difference between a single and a dually rating on the inflation chart, so pay attention to that as well.

[Empty nest]

I’m not sure how your tag axle works as far as dumping the air automatically or manually. On my Tiffin, as long as you don’t go into reverse gear the tag airbags stay inflated. You can manually dump it for slow speed tight corners with the dump switch. If you go into reverse it automatically dumps the tag air. In my case, if I want to weigh the tag or weigh the tag wheels individually (which is what I do) I have to make sure I’m on the scale correctly on the first attempt because if I have to back up it will give me erroneous readings on both rear axles because the airbags on the tag axle will dump. If I have room and can get the coach above 8 mph the tag airbags will re-inflate but 10 mph through a truck stop in a 45’ moho can get exciting.

[boogiejack75]

Originally Posted by TonyMac

I got my rig weighed at the Flying J CAT scale near my home. This scale allowed one side to be on the scale and the other off, some scales don't allow this. I weighed the left side, with the front on the tractor pad and the rear on the trailer pad. Then I weighed the whole thing and did some math. Your tag will necessitate more weighing. Each "tire" weight will have to be computed, the duals are considered one tire in this exercise.

"And the maximum pressure is 130psi for single or duals." Where did you get that? The psi printed on the sidewall is not the maximum pressure. It is the minimum cold pressure to carry the maximum weight, you may see pressures higher than that on your TPMS as your tires heat up.

Wrong. The maximum cold pressure on the tire sidewall will yield the maximum weight rating of the individual tire. The pressure indicated on the vehicle plackard will yield the tire pressure that will support the GVWR of your particular vehicle. The two pressure ratings could be equal or different, depending on the vehicle.

[AccessMaster]

Once you have determined the weight per wheel position, refer to the manufacturers recommended pressure. It will probably be less than the maximum pressure the tire can carry as you load is hopefully less than the maximum weight.
Once this is done the final check that you have it correct for your rig is to check the pressure when cold. Then check it after running at highway speeds for at least 30 minutes. The pressure should be higher than when it was cold, but no more than 10% higher. The pressure increases as the tire heats up. This is normal.
If the pressure does not change, you can actually lower the pressure in 5 pound increments and check again after running at highway speeds.
The tire is designed to work at the proper pressure for the load and at the speed and temperature it is running.
You may have figured out by now that this will work for determining the correct tire pressure even if you do not know the weight on the tire.
May you have a smooth and blessed trip.

[Tireman9]

Originally Posted by DandyDon

I'd be curious to know how many people have absolutely no idea what pressure they should be carrying?? Unfortunately not every RV owner has IRV2 to use as a reference.

Since the data from thousands of weighings indicates that more than 50% of ALL rvs have one or more tire or axle in overload the answer to your question is "Most RV owners do not know or do not care if they are overloading the tires on their vehicle."

[Capt. Bill]

Originally Posted by rayfannin

I have a 2007 Newmar Essex 45' tandem axle class A. It has 315/80R22.5 Michelins all the way around it. Could someone please tell me what the recommended tire pressure should be for them?

Thanks,
Ray

Ray- the correct & only sure-fire way to determine the corresct tire pressure for each wheel is: ensure your fuel & fresh water tanks are full- weigh each wheel on the coach- all 6- add 10% to the weights & then go to the Michelin web site for the respective size tire you have & look up the PSI for the respective load. Remember on your duals to use the dual numbers rather a single tire.


The placard on the drivers side wall near the seat is a manufactures CYA number & will have you inflating your tires to near their maximum & your coach will ride rough as a buckboard!!

I carry 105 PSI in my front tires & 90 PSI on my duals & tag axle tires based on the above procedure.


Happy trails-

[Crasher]

FWIW. Is there any topic that gets repeated more than "Tire Pressure"? How many times can the same question be asked and answered? If people with tire pressure related questions would read the "Newbies Sticky" at the top of this section, a majority of the correct answers to their questions and more are there.

[Ray,IN]

Originally Posted by George Weiss

What nobody has said yet is BALANCE! You must weigh each tire Position. If there is a significant difference left to right, you must relocate some stuff to get differences under 100 lbs if possible. Again, fully loaded for a trip including fuel, food, water, stuff, and people. Then look at weight charts on tire company website. This will give you the correct cold pressure for ride comfort, safety, and tire wear.
If you don’t get position weights you are just playing. Numbers on side of tire or Coach placard or elsewhere are merely what the lawyers make them say. They are not “correct” numbers for anything!

Goodyear disagrees:
"Tire pressure should never be reduced below the vehicle manufacturer's recommended levels to support load conditions in order to improve the ride quality of a vehicle. The difference in ride quality is not significant. When minimum inflation pressure requirements are not met, tire durability and optimum operation can be affected."

[Crasher]

Originally Posted by Ray,IN

Goodyear disagrees:
"Tire pressure should never be reduced below the vehicle manufacturer's recommended levels to support load conditions"

Goodyear doesn't disagree. The key here is "Load Conditions" which even Goodyear states to inflate the tire for the load it is carrying. In other words, weigh each position and inflate to the pressures Goodyear's load inflation table recommends. Of course keeping all tires on an axle equal to the heaviest side.