A Couple Loaded Tires Questions

[MarkF48]

1st question ..... One of the rear loaded tires was looking low and was breaking loose on the rim when pushing snow. I added air to bring it up so as to not look low, but am not 100% sure if checking the pressure with a gauge what I should get. I took a read with valve at the top of the tire so I could use a standard air gauge and got 20 PSI. The tire is an R4 12x16.5 and unloaded I believe can go to 40 PSI for max load rating from the chart in the manual. Does from the wording in 'C' below with 20 PSI measured that I actually have about 21-22 PSI 'corrected' for the diameter and displacement of the juice in the tire?

From tractors manual.......
"For tires equipped with liquid ballast, check the air pressure as follows:

1. Use an air-water gauge. The valve must be at the bottom of the tire to
get an accurate reading.

2. Use a standard air gauge as follows:
A. The valve must be at the top of the tire.
B. Measure the rim diameter.
C. Add 3.5 kPa (1/2 PSI) for each 305 mm (12 inches) of rim diameter
to the standard gauge reading."

2nd Question...... How much liquid of the juice is normally filled into a tire. With the valve at the top I do get the juice coming out of the valve. I was expecting air with the valve at the top. The volume of air space which is compressed is small compared to the volume of liquid which doesn't compress.

 

[atsah]

I check mine at the top of the tire and get the reading it says on the tire. Different size tires get more juice than smaller ones. I do get a dribble of fluid on my gauge even when I check it at the top but that is due to the rim guard all over the place inside the tire. Your reading seems low to me.

 

[skipmarcy]

The general rule on filling tires is 3/4 full - about to the top of the rim +/-. You can put the stem around 12 o'clock and read your pressure with any gauge. The stem will always hold a little of the fluid so if using a regular gauge just quickly depress the core to blow it out first. A tractor gauge can read it wet of course, but you have to hold the gauge on it and read it as the spring will push it back as soon as you take it off the stem to push the fluid out.

My rear tires are 16.9 - 24 R4s, 6 ply. At 3/4 full they hold 55 gal and to get my proper footprint I run 10 - 11 psi and have done so for 17 years with it. My front tires are 12-16.5 R4s, 12 ply and I run them at 38 psi, just 2 psi shy of the max rating as I keep my fel on at all times and use it often. When those 12 ply tires go flat, you can't tell by looking at them they are so stiff. Only with a full load in the bucket can I tell that the tire is low.