Tire Pressure with and without liquid ballast

   / Tire Pressure with and without liquid ballast #1  

Furu

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Years ago when I got my JD 4720 tractor the dealer's service manager told me to run the pressure in the gylcerin-loaded tires on the lower side of the spec values. I have never seen anything to support this and nothing in the manual addresses pressure in a liquid loaded tire as being less than normal.

JD Manual states lower pressure range is for unloaded and unballasted tire.
Specs from manual
Front 10.00-16.5 6 PR 15psi min to 45 psi max
Rear 17.5L-24 8PR 20 psi min to 26 psi max

Do any of the other manufacturer manuals say anything about tire pressure in this regard?
 
   / Tire Pressure with and without liquid ballast
  • Thread Starter
#2  
Should also have asked the following as well. After removing the rear tire for maintenance and trying to handle it on reinstall, does anyone have good techniques for a tire that must weigh in excess of 300-350 lbs. Trying to get it on the axle and align the lug holes was a bear and took two of us to accomplish. There has to be an easier option/method. This was the first time in years that it was ever pulled off.
 
   / Tire Pressure with and without liquid ballast #3  
I put 200 lbs. of wheel weights on by using a floor jack. You might consider that method.
 
   / Tire Pressure with and without liquid ballast #4  
My dealer recommended the same, the logic is that there is now only 1/4 volume of compressible air. So running lower pressures allows for more shock absorption from the remaining air. So the tire "gives" a bit more when you hit a rut than it would at higher pressures.
 
   / Tire Pressure with and without liquid ballast #5  
I can't comment on the pressure, but when I installed my loaded turf's - about 500 #'s, I jacked up the tractor and rolled the tires by hand until the holes lined up...just really needed one to get it started. took me about 5 minutes per side this way
 
   / Tire Pressure with and without liquid ballast
  • Thread Starter
#6  
I can't comment on the pressure, but when I installed my loaded turf's - about 500 #'s, I jacked up the tractor and rolled the tires by hand until the holes lined up...just really needed one to get it started. took me about 5 minutes per side this way

I was feeling that I must be pretty puny if you could do this in 5 minutes and your tires were 500#. I looked up the Yanmar YM2020D and saw the weight was a 2500# specification and decided that my estimate of 300-350 lbs is a bit light by a factor of at least three. That must be my problem, I am dealing with a much, much heavier tire. No wonder I barely can roll it and if the hole was off by even 1/2 diameter the tire had to be readjusted as you could not move it enough to align the hole by rotating the wheel like you would a truck tire. If this tire fell over I could never have manually gotten it back up on the tread.
 
   / Tire Pressure with and without liquid ballast
  • Thread Starter
#7  
I put 200 lbs. of wheel weights on by using a floor jack. You might consider that method.

Good idea.
I was thinking of using something like a transmission jack that never rotates the tire. Thus the holes never get out of alignment and the tire and wheel are pulled away from the tractor and then pushed back in with no change to the axis of rotation of the rim lug holes.
 
   / Tire Pressure with and without liquid ballast #8  
I looked up your tire size (13.6x28 ) and with full ballast, you are looking at around 500 pounds per tire plus any iron weights attached. Easiest is to align one bolt, then use a long pry bar to rotate the tire to align the rest. Get the height perfect or you will be fighting it. Also get some help to make sure you keep that tire upright as it will be a bear to get back up if you drop it. I could manage a 18.4x38 loaded with water in my younger days by myself, but now I struggle with my truck tire so I never try to move tractor tires by myself. I swapped sides with my Yanmar 4220D tire (12.8x28) loaded with water with help from brother in law and hydraulic jack to get height perfect and pry bar to rotate. Took about 30 minutes to do both front and rear tires to widen the stance. Front was easy with FEL for a jack and air impact to turn the bolts.
 
   / Tire Pressure with and without liquid ballast #9  
With regard to tire pressures on loaded vs unloaded, there shouldnt be any difference in pressure between loaded or unloaded.. You are only supposed to fill to about 75% (just cover top of rim) so you still have plenty of air for softening a bump. You should adjust your tire pressue to carry what ever load that you normally have with slight buldge at bottom so that you have a flat tread bar fully across the tire. This will give you the best traction performance and ride. With pressure to high, the outside of the lugs wont contact the ground properly and with too low, you get too much flex in the side walls which isnt good for the tire plus it limits your weight carrying capacity.
 
   / Tire Pressure with and without liquid ballast
  • Thread Starter
#10  
I looked up your tire size (13.6x28 ) and with full ballast, you are looking at around 500 pounds per tire plus any iron weights attached..

Where were able to look that up? It is not in my manual and I can't find it on line with a google search>
 
 
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