Loaded tire pressure

[Soundguy]

Some of my best friends are hayseeds...I wouldn't trade their friendship or practicality for anything. They know more about ballasted tires than you or I could ever hope to.

what kind of a response was that? a red herring diversion and then a slight about my intelegence level?

I know everything i need to know about my tractor tires inflation level when I walk around them in the am before i start working on the machine.. rarely do I ever pull out a gauge and never have i ran into the house for my slide rule.

i'm outta here... math minutia was bad enough.. insults now? later.. go argue with the wall.

oh wait.. one other thing I can think of to improve my happiness today (mouseclick) ahh.. that's better...

soundguy

 

[mustangsallysdad]

Everything under pressure increases its temperature. It is a fact that in a diesel engine the fuel is injected after the air is compressed (Diesel engine - Wikipedia, the free encyclopedia). That is how a diesel engine works.
A fluid does not reduce its volume under pressure i.e. it is non compressible. That is why a loaded tire needs air to prevent bursting.

Find a good book on Thermodynamics and check back after having read it thoroughly. It's much more complicated than that.

 

[RickB]

Some of my best friends are hayseeds...I wouldn't trade their friendship or practicality for anything. They know more about ballasted tires than you or I could ever hope to.

Don't include me in that. I AM a hayseed, and I do know more about ballasted tires than you. I've owned and operated farm tractors all my life doing work that required proper ballasting for efficiency.
I've also probably driven tractors in reverse farther than you ever will in a forward direction. But saying that would be rude and condescending, and I'm not like that.

 

[Soundguy]

my bad.. it's more like (mouseclick) (mouseclick) (mouseclick) (mouseclick) to add someone to an ignore list... not just the single (mouseclick) I indicated earlier

soundguy

 

[mustangsallysdad]

Don't include me in that. I AM a hayseed, and I do know more about ballasted tires than you. I've owned and operated farm tractors all my life doing work that required proper ballasting for efficiency.
I've also probably driven tractors in reverse farther than you ever will in a forward direction. But saying that would be rude and condescending, and I'm not like that.

No Rick...I believe in giving credit where credit is due...you are like that...and this wasn't my dissertation...that was "Aerodynamic Properties as Proven by Bernoulli's Principle". Mouseclick as well...outta here!

 

[mustangsallysdad]

what kind of a response was that? a red herring diversion and then a slight about my intelegence level?

I know everything i need to know about my tractor tires inflation level when I walk around them in the am before i start working on the machine.. rarely do I ever pull out a gauge and never have i ran into the house for my slide rule.

i'm outta here... math minutia was bad enough.. insults now? later.. go argue with the wall.

oh wait.. one other thing I can think of to improve my happiness today (mouseclick) ahh.. that's better...

soundguy

"intelegence"???

 

[SPYDERLK]

There are a few things to consider.
1] The compression ratio inside a filled tire is much greater and so the pressure will rise quickly as the tire deflects as it begins to bear more weight.
2] How varied are the weights of the implements used.
3] How varied are the amounts of tractive force that are required to pull the load?

Due these and other incidentals I run a range of pressures decided by how the tractor looks when configured for the job at hand. I want to see 2 bars touching to the edge on each side of the tire. This gives a little bulge that I consider no problem. What I dont want is to see is much sidewall crinkle next to the tread bars under consistent pull load conditions. Any significant crinkle beyond momentary is cause for more inflation pressure. Due to the higher compressional stiffness, and the fact that the fluid filled tire has 1 to 2 psi greater internal pressure at the bottom, I find that pressures can be run 2 or 3 psi lower. Depending on the job and tractor weight I will run anywhere from 5psi up. Fronts are often near their peak rated pressures. Rears almost never.
larry

 

[Aaron_D]

Wow... Hate to jump into this storm but... The compressibility of the ballast liquid has no affect on straying from your mfg recommended tire pressure. Yes liquids are not incompressible (nothing is) but due to their low compressibility they are often assumed to be so. Additionally the change in temperature changes the density vastly more than pressure and even if the density changed, the pressure is equal throughout.

In a standard automotive tire for every 10 degrees the pressure changes approximately 1 psi. As a tractor tire has way more volume, it should be more. Adding a liquid would reduce the volume of air changing the affect of density. As SPYDRLK stated, lowering the volume of air does slightly change the way your tire reacts to tire deflection by requiring the air to compress more per its volume making the ride more harsh. It doesn't change the internal pressures the tire see's though.

Keep the pressure the same. By that I mean that your pressures should reflect your usage and load at the time. There is no 1 perfect tire pressure. The mfg recommended pressure is the starting point (general one size fits all) but usage dictates the proper pressure for your need. Just don't exceed the max pressure rating on the tire.

 

[The Haymaker]

Man, am I doing things the hard way. On my loaded tires, I inflate them until two criteria are met.

1) The tire is not flat on one side.

2) The tractor does not lean at more than a 45 degree angle left or right.

Is this killing my mpg?

 

[SPYDERLK]

As SPYDRLK stated, lowering the volume of air does slightly change the way your tire reacts to tire deflection by requiring the air to compress more per its volume making the ride more harsh. It doesn't change the internal pressures the tire see's though.

Keep the pressure the same. By that I mean that your pressures should reflect your usage and load at the time. There is no 1 perfect tire pressure. The mfg recommended pressure is the starting point (general one size fits all) but usage dictates the proper pressure for your need. Just don't exceed the max pressure rating on the tire.

Sure it does. Beyond the static inflation condition, equal additional deflection in a filled vs unfilled tire will cause a higher pressure in the filled tire. This prevents the filled tire flattening as much as the unfilled under equal load. For this reason you can run the filled tire softer in general, giving a good ride and still not too much squat under heavier loads.
larry