Airing up the tires

[powerboatr]

Does anybody know if the air system quick port up front under the hood(front genny access panel) will air up the tires to 120 psi?
i got em to 113-114 using my 125 psi air compressor in the garage, they were at 103/104 before our trip, but it took over an hour of squeezing in a few pounds then bleeding the compressor so it come on then getting a few more pounds out, etc etc

[RVDude]

The quick answer is probably not 120psi. What does you air gauge read on the instrument panel? That's the pressure at that access port. If it does go above 120psi you will also probably need to bleed air (apply brakes repeatedly-if air brakes) like you bled your home unit to get it to cut in and build higher chassis pressure.

[Danorske]

Why do you need so much air in the tires?

[powerboatr]

Quote:

Originally Posted by Danorske Why do you need so much air in the tires?

sidewall 120psi
we are heavy 29000 lbs

[RVDude]

Sidewall does not equal proper inflation! The sidewall is only the MAX inflation for its rated MAX load.

You need to weigh your rig, each wheel is best but the local truck stop axle scales at $7 are fine and then use the tire manufacturer inflation tables (on the web site for your tire maker) based on your tire weight! That then is the inflation psi for the temperature (undriven=cold) you are in.

There is simply NO other answer for inflation pressure.

[powerboatr]

gvwr is 32k, rear gawr is 20k, front gawr is 12k
according to goodyears tables at max gross weight i should be running 105 up front and 95 in the rears, there is no way i am running those puppies at 95 psi,

i weighed her Saturday,
total 29920 lbs
rear axle 19300 lbs table shows 90 psi for the rear set at 4825 lbs on each wheel.
front 10620lbs table shows 90 psi for fronts at 5310 lbs on each wheel

still there is no way i am running these big tires at 90 psi
i may now drop down to 104-107, and see how they wear and monitor temps when i stop.

107 is much easier to achieve with my onboard and home compressor

[RVDude]

Now I am really curious. May I ask why you choose not to run them at the recommend psi for the actual weighed axle weights? Your actual weight is well under the theoretical max weight, the GVWR. I can see going 5 or so psi over to account for a side to side imbalance due to axle only weighing. But why so much more psi than that (15-30psi more)? You'll get a smoother ride and longer mileage as you won't be center wearing the tires. Just curious as to your rational. Thanks...

BTW - I run my 22.5 rears w/tag at 85psi all carrying just shy of 30,000 lbs on the rears alone (~5,000lbs ea). The actual axle/tire load is well below my tire manufacturer table weights but there is also a minimum inflation as well (lowest on the tables) and for me that is 85psi on my rear tires. My fronts carry about 8,000lbs ea and the table has them at 120psi for the same tire as the rears.

[Route 66]

There is absolutely no reason to inflate tires above the pressure to carry the load.

Higher pressures result in a harsher ride and less traction, as the tire is not making proper contact with the road.

I carry 85 psi in my rear tires which is recommended for an actual weight of 20,000. There is no problem with 85 psi, if that's the proper psi for the load.

[wa8yxm]

This is a post I make often: Two tire pressures all but guaranteed to be wrong are

1: The sticker inside the coach (That is the proper pressure for the coach with 1/2 tank of gas, no water, no waste, no cargo, and one 150 pound driver, no passengers)

2: The pressure moulded in the side of the tires.

Far too many people read "Max pressure 120 PSI"

That is NOT what it says IT has NEVER said that.

IT says somethign like: Maximum load 20,000 pounds at Max pressure of 120 PSI

if you are only running 15,000 pounds. use less pressure

The proper way to air 'em up is to scale the wheel RV Safety, Merritt Island, Florida will do that for you for a fee. Then they will tell you what to blow 'em up to.

[powerboatr]

Quote:

Originally Posted by RVDude Now I am really curious. May I ask why you choose not to run them at the recommend psi for the actual weighed axle weights? Your actual weight is well under the theoretical max weight, the GVWR. I can see going 5 or so psi over to account for a side to side imbalance due to axle only weighing. But why so much more psi than that (15-30psi more)? You'll get a smoother ride and longer mileage as you won't be center wearing the tires. Just curious as to your rational. Thanks... BTW - I run my 22.5 rears w/tag at 85psi all carrying just shy of 30,000 lbs on the rears alone (~5,000lbs ea). The actual axle/tire load is well below my tire manufacturer table weights but there is also a minimum inflation as well (lowest on the tables) and for me that is 85psi on my rear tires. My fronts carry about 8,000lbs ea and the table has them at 120psi for the same tire as the rears.

i may drop em a bit more, but not until i run a few more miles and see how they are wearing or tracking across the tread, believe me if i can run them lower safely to match the actual load, i may chalk the tread and roll across my concrete pad to see what the contact patch looks like.

just hard to believe these tires are that strong....

[soonerdave]

To answer your original question, there is a quick-disconnect under the "hood" for an air pressure hose. When you open the hood look up and a little to the left, it is right next to the hydraulic jack pump. I have never put a gauge on to see how much pressure is available. According to the dash gauges the pressure should be around 110 psi, give or take.

[The Woodieboys]

OK, we just weighed again last month and have our tires adjusted for 90 PSI in the fronts and 85 PSI in the rears. The same as when we weighed last year and the year before.

We have run these pressures in the tires since we have had our coach and it handles much better with the correct pressure in and the tire wear is perfect. I was freaked out at first thinking that the tires were way too low but called Goodyear and they confirmed that they should be inflated to the weight chart. It keeps the heat down and keeps the proper tread contact with the pavement.

[powerboatr]

Quote:

Originally Posted by The Woodieboys OK, we just weighed again last month and have our tires adjusted for 90 PSI in the fronts and 85 PSI in the rears. The same as when we weighed last year and the year before. We have run these pressures in the tires since we have had our coach and it handles much better with the correct pressure in and the tire wear is perfect. I was freaked out at first thinking that the tires were way too low but called Goodyear and they confirmed that they should be inflated to the weight chart. It keeps the heat down and keeps the proper tread contact with the pavement.

this next trip i am going to drop the fronts to 97 and the rears to 95, see how they roll, I think i also need to move some weight off the front axle towards the rear, dont know how, with these 6 slides , maybe less biscuits and gravy for the driver

[two gone rvn]

Anybody ever put a infared temp gauge to one and see what the temps were after a few hours of driving? Just courious.
George