Tires Tire ressure question

[tillboy2001]

I have a 4120 with R4 tires. When I checked the pressure on the front tires they were pretty much in line with what the book said. When I checked the rear, it didn't even barely register on the gauge. Here's what the book says for the rear tires for R4:
Rear Tire Inflation Pressures
NOTE: Minimum / Maximum pressures given. Minimum pressure is for unloaded, unballasted tractor.
17.5L-24 8PR R4 TI 138 kPa/180 kPa (20 psi/26 psi)

I went ahead and put air in them until it registered 17 lbs on the gauge. What are you guys running? I wonder why it didn't even register the first time I checked? They didn't 'look' low but they sure took a lot to get them up to only 17 lbs. I didn't even go to the low end of the recommended pressure (20).

 

[RoyJackson]

Are those rear tires filled?

I don't think the stem type pressure gages are particularly accurate at low pressures, so if it wasn't registering, you probably had 10 to 12 PSI in the tires.

There is a lot of volume in those rear tires. Depending on the air hose pressure and CFM of your compressor, it can take a while to up the pressure. If your tires aren't filled, it'll take even longer.

I have my ancient (it was my father's actually) Sears compressor set at 120 psi. I don't know what CFM it pushes through, but probably not more then 10. Mine takes a while to fill the tires too. My tires are filled (~75%), so that reduces the volume quite a bit.

I run about 15 to 20 PSI in the rear tires. 20 PSI in the fronts, but I up that when I'm using the loader.

 

[tillboy2001]

Rear tires are not filled. I've got 220 lbs of weights on each side. I might try a different gauge and see what it says. It did take awhile to fill to this point, as you said, because of the volume. Maybe I better get a more sensitive gauge and see it they read over the max pressure. I don't want to leave them this way for too long if I'm uncertain about the pressure that's in there right now.