Ballast rim guard and proper inflation

[ovrszd]

You posted that "Cubic feet of air not pressure carries the load." Boyles law and the definition of pressure and volume contradict your statement. "The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system" By its definition it is the pressure exerted on the walls of the closed system that allows the pliable container to resist deformation. In this case your tire. The volume only describes the interior of the 3 dimensional space your tire contains. The volume of your tire will not change as long as you don't punch a hole in it. So if the volume is fixed, the only variable here that you can affect is the pressure. Occasionally mother nature will affect temp.

I think I understand your statement.

That Big A loaded with fertilizer will gross 27-30K on three tires. That's 9-10K per tire. Does it with 2-3 psi. Using your explanation, it is the pressure exerted on the walls of the closed system that allows the pliable container to resist deformation, how can that be?

No argument here. Just looking for clarity. I'm always open to learning.

 

[murphy1244]

Well, it's not my Big A and not sitting in my driveway, but I would if I could.

I deal with tire pressure all the time in many different sizes of tires. I normally run 4-6 psi in my buggy tires which weighs 4000 lbs with more squat than that Big A's tires. How can that be?

Again, run your own tests. Grab a gauge and air down your pickup tire to 4-6 psi and take a pic.

Again, I'm not a book educated philosopher. I base my knowledge on personal experience. Maybe the more educated can explain to everyone why the rear tire of our tractors require less psi than the front tires?? Think about it a second before answering.

Sorry thought it was yours.

 

[ovrszd]

Sorry thought it was yours.

No worries. Help me understand this Murph???

 

[murphy1244]

No worries. Help me understand this Murph???

I have a tire on my truck that loses air over time. Before I see fill it up it only has about 15psi in it and it is way down. The tire print and psi is what does the weight. I think you are over thinking this like the ballast on 3 point again. Most of us don't know how to win a fire fight but you do. No worries. Did I explain it right?

 

[adventure bob]

Not taking any of this as argument, and pls don't take it as anything other than conversation. I know the internet has no tone so sometimes its taken out of context.
The volume is just the 3 dimensional measurement of the internal dimension of the tire… its just a measurement of space. In this case tires hold cubic feet of air (ft3). In this case the shape of the container is fixed, thus fixing the volume. Lets for grins say that the volume of the tire is 10ft3. It has that volume whether it has anything in it or not. If you take the valve stem out, you still have a volume of 10ft3 with an internal pressure equal to ambient air pressure, 14.7PSI, or 0PSI since air gauges are calibrated to ambient air pressure. At that point the internal pressure and external pressure of the tire is exactly the same, and unless the sidewalls are holding up the load, the tire will be flat on the bottom. You have said that this is not the case with these tires, so I'm assuming that when they're at zero they are flat on the bottoms. Even though they’re flat, the volume of the tire is still 10ft3, the thing you vary by "putting air in the tire" is its pressure. You can’t change the internal size of the tire, your increasing the pressure of the gas contained in that volume, it’s still only 10ft3. As the pressure exceeds the 14.7PSI it will begin to expand the flexible container, lifting the vehicle up as the pressure increases. If we take the same tire and do the rimgaurd thing, we have filled part of the 10ft3 with a non-compressible liquid, beet juice, and the rest of the volume with air. Its still 10ft3 of volume, just some of it is not compressible. You can then use the remaining volume of air to achieve a pressure that results in a contact patch you’re looking for. Additionally, you get some shock absorption

 

[ovrszd]

I don't take any of this as argument either. Very good discussion.

So, because the Big A tire can hold up 10K lbs of weight at 3 psi is because of cubic ft of space?

So, it's actually doing it with volume not pressure?

If the answer is yes to these questions I rest my case.

P.S. Love ya Murph.

 

[adventure bob]

The answer is no, as I stated volume is just a measurement of 3d space. Pressure is a measurement of force. The amount of force pushing against the outside of the tire and causing it to be able to lift the vehicle. You have asserted that somehow something measured in ft3 has the ability to assert a force. Its simply a measurement of 3d space like a liter, or a cup, or a cubic yard.

 

[Citydude]

The 797B runs 87 pounds of air in their tires. We targeted 400 tons a load on them. My F250 requires 70 pounds.

 

[murphy1244]

The 797B runs 87 pounds of air in their tires. We targeted 400 tons a load on them. My F250 requires 70 pounds.

Now that is alot of foot print there.

 

[lilranch2001]

The 797B runs 87 pounds of air in their tires. We targeted 400 tons a load on them. My F250 requires 70 pounds.

so...... you can load over 300 tons on it???:confused3:
Well as long as the aluminum does not deform