Tire pressures and my air compressor

[HighwayJunky]

Ok, so granted I am not the heaviest brick in the load so thought I'd ask this question. It might be simple logic but I want to be sure. My RV tires are to be at 130PSI front and 120PSI rear.

My air compressor states that it has a maximum pressure or 150PSI tank pressure. So,if this is running properly it should fill the tires to their respective pressures. Right? Should I assume that since the tire pressure is to be 130 and the max pressure from the compressor is 150 then the amount added is only 20PSI and it a very slow rate??

Or should I get a higher PSI capacity air compressor to do the job?

[parkmanaa]

QUOTE FROM SIDECARFLIP'S POST:
"I disagree with your premise that the center of the tire will wear down in no time or the unit will ride like a brick. Tires are designed to run at maximum listed sidewall pressure and tires provide very little compliance (flex) when rolling. The suspension provides ride compliance (comfort) not the tires. Tires are designed to carry a load with minimal flex (which causes internal heat), not provide a comfortable ride."

SIDECARFLIP, you need to do a little more study on the design of radial tires. Radial tires are designed TO FLEX IN THE SIDEWALL, because the tread is stiffened to prevent it's flexing. Also, the air pressure in radial tires will definitely have an effect on ride and tread pattern wear.
"designed to carry a load with minimal flex" certainly applied to the old bias ply tires, for if they flexed the scissors action within the plies would cause heat buildup and eventually failure.
The secret to radial tires is to have the PROPER air pressure, not too much, not too little, for the load you are carrying on each tire. Provided you have the correct pressure, the belts in the tread are flat with the road, very little stress on shoulders or center of tread; result is nice ride and wear pattern.
Sorry to take so long, but after dealing with radial tires for 40 years, I just couldn't let this one get by me.

[Ohio_Engineer]

Hopefully you only need to "top off" your tires (add 5 to 10 psi). If that is what you need than air volume isn't an issue.
If you need to add more there is something wrong and the tire may have structural damage. I would only have a professional shop do the inflation (in a cage) if I needed more than 10% to the pressure.

[Tom_Barb]

CharlesinGA wrote:

Tom/Barb wrote:
Remember folks, the tire valve core has a basic opening pressure. your compressor must at least have that pressure over the desired pressure to get the air into the tire.

want to prove that? use an old rubber tire filler with a core in it, connect it to your compressor, set the regulator at 0 and slowly add pressure until the valve core opens.

Ive seen them as low as 10 psi, and as high as 80 psi.

Valve core is pushed open by the metal peg in the center of the chuck that also opens the chuck. Want to prove it? take a chuck, not connected to an air hose and push it on the core, air comes out because the chuck opens the core.

Charles

If one of those low pressure fillers is what your using sure, but those who use a little home shop air compressor don't want to hold it that long for coach tires.
mine screws on and works on a pressure differential.

[CharlesinGA]

Tom/Barb wrote:
Remember folks, the tire valve core has a basic opening pressure. your compressor must at least have that pressure over the desired pressure to get the air into the tire.

want to prove that? use an old rubber tire filler with a core in it, connect it to your compressor, set the regulator at 0 and slowly add pressure until the valve core opens.

Ive seen them as low as 10 psi, and as high as 80 psi.

Valve core is pushed open by the metal peg in the center of the chuck that also opens the chuck. Want to prove it? take a chuck, not connected to an air hose and push it on the core, air comes out because the chuck opens the core.

Charles

[jtfcons]

A 150 psi compressor means that it shuts off at 150 psi, and turns on at some other pressure (???). Don't know what your unit does in this case but if it is below 130 psi you will have a problem filling a 130 psi tire because when getting at or near this level the air flow will stop or severely slow down. If this is the case you will have to force the compressor to turn on by using a hand nozzle to get it to turn on and begin filling to the 150 psi shut off point. You can fill the tire in this cycle. Hope that makes sense.

[wolfe10]

rhagfo wrote:
Got to ask why not just tap your air brake system for air most likely provides 150 psi and should be easy to tap the supply tank.

No, most DP air systems cut out around 120 PSI. Yes, that should be adequate for most coaches, but certainly not if 120 PSI or above is needed.

[rhagfo]

Got to ask why not just tap your air brake system for air most likely provides 150 psi and should be easy to tap the supply tank.

[Tom_Barb]

HighwayJunky wrote:
In reply, Tires are Michelin's and are 2.25. New coach and labels say pressures at to be set at 130PSI for front and 120PSI for rear. 38'ft MH. 31000 lbs

What rims do you have? truck Steel Type?

[HighwayJunky]

In reply, Tires are Michelin's and are 2.25. New coach and labels say pressures at to be set at 130PSI for front and 120PSI for rear. 38'ft MH. 31000 lbs

[Tom_Barb]

Remember folks, the tire valve core has a basic opening pressure. your compressor must at least have that pressure over the desired pressure to get the air into the tire.

want to prove that? use an old rubber tire filler with a core in it, connect it to your compressor, set the regulator at 0 and slowly add pressure until the valve core opens.

Ive seen them as low as 10 psi, and as high as 80 psi.

[Bikeboy57]

The rate at which the tire will fill is directly controlled by the difference in pressure between the tank and the tire. Make sure the regulator on the outlet is set to maximum.

I owned a coach that required 130 on the fronts. The porter cable pancake compressor rated for 150 psi filled them just fine

[Ivylog]

Weight your rig...doubt you need that much pressure.

[Tom_Barb]

Just for your info, my 10 X 22.5 aluminum rims are stamped "120 PSI maximum"

tires = same thing, right on the tire sidewall.

[Mr_Mark1]

I have the Porta-Cable pancake 150 PSI compressor that I bought at Lowe's. I have no idea what the CFM (cubic foot per minute) is on this unit. I can tell you it is kinda slow but it gets there.

We have Michelin 365's on the front and tag of our coach with 315's on the drive axle. My target pressures are 115 for the fronts, 100 in the drive and 90 in the tags. We weigh 55,500 lbs. I keep an extra 3-4 lbs. for insurance.

The OP'ers pressures do seem high but it does depend on the tire. I would certainly get the coach weighed on four corners and then use the tire manufacturer charts.

Safe travels,
MM.