Ballast rim guard and proper inflation

[ovrszd]

I bet the F-650 with regular tires rolls on firm ground with less friction though.

Absolutely. We even notice that resistance on our buggies running large tires at 4-6 psi.

 

[Texasmark]

Some things I have a hard time understanding. So I try to be compassionate with others in that struggle.

The interesting thing about this post and it occurring when it did is that I am right in the middle of such with my little 2400 and tweaking for best ride. I had some non-scientific ideas as to relationships between to fill or not, if so, how much, air pressure minimum and the ability of the tire to remain on the wheel under selected conditions.

So the subject hit home with me. Right now I'm waiting on $600 worth of 2 ea. 4 ply turf tires (geez I can't believe where prices on tires have gone) to replace my OEM 6 ply, stiff sidewall industrials, that I will load to about 5 psig and probably 75% fill.

Will try them dry first but probably will wind up with fill as I have proven weight rides smoother on low air pressures as long as you have enough air volume to absorb the impact of a hard bump without significantly increasing pressure which transfers to the seat and my back. If that doesn't work I'll try something else.

 

[ovrszd]

The interesting thing about this post and it occurring when it did is that I am right in the middle of such with my little 2400 and tweaking for best ride. I had some non-scientific ideas as to relationships between to fill or not, if so, how much, air pressure minimum and the ability of the tire to remain on the wheel under selected conditions.

So the subject hit home with me. Right now I'm waiting on $600 worth of 2 ea. 4 ply turf tires (geez I can't believe where prices on tires have gone) to replace my OEM 6 ply, stiff sidewall industrials, that I will load to about 5 psig and probably 75% fill.

Will try them dry first but probably will wind up with fill as I have proven weight rides smoother on low air pressures as long as you have enough air volume to absorb the impact of a hard bump without significantly increasing pressure which transfers to the seat and my back. If that doesn't work I'll try something else.

Make sure to post your results. Maybe start a new thread about it. I know there are several members here that discuss this periodically.

I have my rear tires filled. I think it rides better actually. I think that comes from adding weight to the tractor so it doesn't bounce over bumps as much. Kinda mashes it's way thru them.

Anxious to hear your thoughts about the change.

 

[Cougsfan]

Just to add my 2 cents (maybe a dime now due to inflation); The air in a tire doesn't hold the vehicle up. The sidewalls do. Air, as we know, is quite compressible and won't support a load. All air does is rigidize the side wall so it won't collapse under the load of the vehicle. It is very much like pre-stressing a beam. The more air pressure you have; the more pre-stress you have and the sidewall will deform less. Although the air pressure is exerted evenly across the entire interior surface of the tire, it only really stops (or reduces) the deformation where the load is trying bend the sidewall; just above the tire contact point. And it is all the compressed air inside the tire doing this chore, not just the air by the deflecting sidewall. When you fill the tire almost full with a noncompressible fluid (rimguard) plus some air, the fluid transmits the force from the sidewall to the air up at the top of the tire down to where the sidewall is trying to deform, and that air pressure still keeps the side wall from deforming.

Another thing to keep in mind is that air in the tire acts to allow the sidewall to act a kind of suspension for the vehicle. As outside forces, such as a rock or curb, tries to deform the side wall, the air pressure allows the sidewall to deform some (more pressure, less deformation), and the disruption caused by the rock or curb is dampened by that deformation.

 

[Billrog]

Maybe a pic. as i'm having difficulty understanding some of the explanations here. With air being contained within the tire the greater the pressure the less distance between the molecules reducing the amount they freely compress. Like in the pic. where the cold molecules are much closer together.

 

[Cougsfan]

It doesn't matter if the air is hot or cold, high pressure or low pressure, the air itself has close to no strength to support anything. If air could support stuff, things wouldn't fall if you drop them. What pressurized air can do is exert pressure equally in every direction. Inside a tire and wheel assembly, pressurized air is doing just that. It it pushes against the tire, the rim and everything it touches with equal force in every direction. It pushes up, & down, (against both the tire and the wheel) and every version of sideways. The more pressure, the more force. As the pressure is increased, the tire itself becomes so rigid that it can't flex because of that pressure pushing against these surfaces. The tire becomes so rigid it will support a vehicle without collapsing.
Another way to look at it is that the compressed air is pushing upward against the wheel with the same force that it is pushing downward against the tire/ground contact point. If that up/down force created by that air pressure exceeds the downward force exerted by the vehicle due to gravity, and the sidewalls have enough rigidity to not fail, the vehicle isn't going to sink toward the ground.

 

[Texasmark]

Make sure to post your results. Maybe start a new thread about it. I know there are several members here that discuss this periodically.

I have my rear tires filled. I think it rides better actually. I think that comes from adding weight to the tractor so it doesn't bounce over bumps as much. Kinda mashes it's way thru them.

Anxious to hear your thoughts about the change.

I'll keep you in mind. Dealer had to get them out of a Titan warehouse somewhere up North. Said it would take 2-3 weeks as they were in a shipment he had coming anyway and that way he said I'd save the freight. With the weather we've been having it may be a couple more weeks.

 

[Texasmark]

Just to add my 2 cents (maybe a dime now due to inflation); The air in a tire doesn't hold the vehicle up. The sidewalls do. Air, as we know, is quite compressible and won't support a load. All air does is rigidize the side wall so it won't collapse under the load of the vehicle. It is very much like pre-stressing a beam. The more air pressure you have; the more pre-stress you have and the sidewall will deform less. Although the air pressure is exerted evenly across the entire interior surface of the tire, it only really stops (or reduces) the deformation where the load is trying bend the sidewall; just above the tire contact point. And it is all the compressed air inside the tire doing this chore, not just the air by the deflecting sidewall. When you fill the tire almost full with a noncompressible fluid (rimguard) plus some air, the fluid transmits the force from the sidewall to the air up at the top of the tire down to where the sidewall is trying to deform, and that air pressure still keeps the side wall from deforming.

Another thing to keep in mind is that air in the tire acts to allow the sidewall to act a kind of suspension for the vehicle. As outside forces, such as a rock or curb, tries to deform the side wall, the air pressure allows the sidewall to deform some (more pressure, less deformation), and the disruption caused by the rock or curb is dampened by that deformation.

Interesting your comments. I had 75% fill and had the rear jacked up to where the tire was just resting on the floor. I was seeing just how far I could let the air out and still have control of the tire against the wheel rim. As long as I had a pound or two of pressure in the tire it remained attached to the rim of the wheel. When I backed out the stem and arbitrarily let it all out, the tire immediately collapsed with the weight of the fluid and mixture came gushing out the sides of the tire.

I'm finding out that I can run 75% fill and 5# for a reliable, relatively soft ride with no implements attached. When I go to attach an implement I'll pump them up to 10 or so watching the sidewall for a tad of flexing. Interested to see what happens when I mount the turfs maybe this week or soon I hope.

 

[Cougsfan]

I'm finding out that I can run 75% fill and 5# for a reliable, relatively soft ride with no implements attached. When I go to attach an implement I'll pump them up to 10 or so watching the sidewall for a tad of flexing. Interested to see what happens when I mount the turfs maybe this week or soon I hope.

What kind of tires do you have on now, Texasmark? I am still working at seeing how low a pressure I can go with the r4's on my new Branson. I would agree that you are best off running the lowest pressure you can safely go without breaking the bead or spinning the tire on the rim. That minimum pressure is quite different based on individual tires. Oddly, when I first filled my tires with Windshield Wiper Fluid, I had to run them over inflated at first just to keep the beads from seeping WW fluid. As the rims and tires age, I think they will seal and stay on the bead better. I never bothered trying to lower the pressure until it started snowing around Thanksgiving. Now I have started slowly running the pressure down (no leaks!) for more traction on the snow.

 

[lilranch2001]

I got lazy and failed to check my air pressure in my rears
Turned out the pressure got too low and one bead broke and spilled rim guard out all over my floor
Now I too am curious as to what "to low" is