Tire Inflate Quicker w/ no load ?

JIMNLIN wrote:

Old-Biscuit wrote:
Have your 'friend' check the air pressure in his MH tire...record it

Then have your 'friend' take the load off of that tire and re-check the air pressure


Hummmmmmmm?
Air pressure the same!

Y
Yeah...I've taken many a ruined tire off a loaded trailer with 1750 lb up to 10000 lb trailer axles when I was on the road. Had the tire guy add the max sidewall psi to the tire. Drove back and mounted the tire on the loaded trailer...removed the jack and rechecked pressures. Always the same.

Maybe, with a cheap tire pressure gauge. But the pressure does increase as more load is added to a tire. Just not enough to matter. It's elementary physics.

Old-Biscuit wrote:
Have your 'friend' check the air pressure in his MH tire...record it

Then have your 'friend' take the load off of that tire and re-check the air pressure


Hummmmmmmm?
Air pressure the same!

Y
Yeah...I've taken many a ruined tire off a loaded trailer with 1750 lb up to 10000 lb trailer axles when I was on the road. Had the tire guy add the max sidewall psi to the tire. Drove back and mounted the tire on the loaded trailer...removed the jack and rechecked pressures. Always the same.

Goolge Boyles Law.

Old-Biscuit wrote:
Have your 'friend' check the air pressure in his MH tire...record it

Then have your 'friend' take the load off of that tire and re-check the air pressure


Hummmmmmmm?
Air pressure the same!

In my previous post, I did that, and recorded no difference on an analog. But supposedly working w/ approx 100 lbs pressure, a digital gauge will show approx. .5 less pressure unloadad,...same as no difference.

Forgot to say that the problem is airing tires to 90 psi using a 100 psi compressor. It really does take forever.

Have your 'friend' check the air pressure in his MH tire...record it

Then have your 'friend' take the load off of that tire and re-check the air pressure


Hummmmmmmm?
Air pressure the same!

The trifle less volume in a squashed tire would make it theoretically air up faster maybe a few milliseconds. Relieving all the weight on a highly loaded tire would reduce air pressure ever so slightly.

You have to put X number of cubic inches of air into the tire to raise the pressure by 1 psi. The 3 things that affect that are the size of the compressor's piston, the pressure the compressor puts out, and the pressure in the tire.

The bigger the compressor piston, the more air it will move in a unit of time. (Big compressor good, small compressor bad.)

The pressure of the compressor is almost a constant. It is determined by the size of the compressor piston and the RPM's it is running.

As the tire's pressure rises, the air will flow in slower. That is why a flat tire airs up rapidly right at first, then slows down considerably as it gets fuller.

The one thing that won't affect this is the load on the tires from the vehicle.

I can understand that.. But it is way more complex.

I do not think they inflate faster no load. in fact even though you might think they do It may be the reverse.

RJsfishin wrote:
A friend said his MH tires air up quicker when he unloads the weight.

The limiting factor in airing up tires, presuming he’s concerned with speed rules out hose size, is the difference between air supply and air already in the tire.

Air, like water or nearly anything, will flow faster from high pressure to low pressure than it will from high pressure to high pressure.

As for unloading first, as stated, nope, no difference. Think of it this way, you measure tire pressure with the rig up on jacks, no load, then lower it to the ground, loaded, then measure again. Did the pressure reading change with the ‘added load’? Nope.

Well, its hard to disagree that the more weight you place on a tire, the higher the pressure will go. That idea comes from the fact (is it fact) that if you could/would continue adding weight, the tire could eventually blowout from excessive pressure.
So I can believe that if the tire is unloaded, it will have less pressure in it, and in theory would inflate faster. But when I did it, loaded and unloaded, I couldn't see any difference on my analog air gauge. When I google it, at 100 lbs pressure, you would see only about 1/2 lb difference on a digital gauge.
So I conclude my friend is correct in theory, but not in actuality.