You can measure the air pressure with a normal air pressure gauge when the tire is filled with the proper amount of fluid and with the air valve at the top.

You should have some air in fluid filled tires; otherwise, they'll ride like rocks. The fluid should be below the air valve when the air valve is in its topmost position.

-Deerslayer

As deerslayer said, just use a regular tire pressure gage. I suggest getting one that is the 0-20 psi range since you only need about 8-12 psi on these tires. A higher range gage may not be accurate for such low pressures.

I just read the two above posts to my husband, he said this may ruin the tire gauge and render it unreliable for other tires. He also said the JD manual says to put the valve on the bottom of the tire when testing and use a special air-water gauge, which JD did not have.

Nancy

Try your local tractor supply store or other farm parts store. Yes your husband is right this may ruin a regular air gauge and the valve should be at the bottom when checking the pressure. You may even check at a tire repair shop for one, at least they could send you in the right direction to get one locally.

You can find one here:

http://www.amazon.com/s?ie=UTF8&rh=n%3A15706701&page=8

Bottom of the page and sells for $8.95.

"... and the valve should be at the bottom when checking the pressure."

What kind of Bull shet is that?

It does not matter where the valve stem is located. The pressure in the tire will be the same.

Go to a Motorcycle or ATV shop and get one made for low pressure tires. 0-20 PSI range as machiem suggest. Place the valve at the top and check the pressure..

For it will be hard to find a tire gage that will work correctly when filled with fluid unless you get one made for full sized heavy equipment tires that will cost a good penny and need a bunch of adapters to work on a lawn mower tire.
=========================================================

Now you can do all of that. Or do as Hippy does with a simple trick that he applied when racing ATVs.

Pick the rear of the machine up off of the ground.
Get a tape measure.
Measure around the center of the tire.
When both tires measure the same dia.
No matter if one has 10 PSI and the other 15.

They will both be equal in height and give a level ride.

hippy, I think she is asking about a regular farm tractor's rear tires. She asked about some clutch ajustments on another thread for a 5425 John Deere. That is 65 pto hp farm tractor 81 hp on the engine, that is no lawnmower. lol

Nancy, if you have a real tractor. Here's where you can order a tire gauge:

Tractor Tire Gauge

This forum focuses on lawn and garden tractors. That's what I assumed you had in my first response.

-Deerslayer

This post got me thinking. With a fluid filled tire, measuring with the air valve at the bottom will give a different reading than with the air valve at the top. This is because the weight of the fluid increases pressure. The difference may not be that significant with short LT & GT tires but it could be significant with a full size tractor tire.

-Deerslayer

"Tractor Tire Gauge" link.
We have one of these. If your tire is filled with alcohol and you use this gauge, this can damage the gauge. We need a separate gauge just for fluid(alcohol) filled tires. This particular tractor is indeed large, not a lawn tractor. Tho our smaller 38 hp MF also uses alcohol in the rear tires.
As this forum was headed Tractor, I did not realize it meant lawn(small) tractor. Sorry if I posted on the incorrect forum. When we needed a zeroturn mower, this forum was very informative and ever so helpful to us.

Nancy

Nancy, quite frankly you're starting to pi$$ me off. In your original post, you didn't indicate that you have a full size tractor and you didn't indicate that you have tires filled with alcohol. If you can't ask a good question, don't expect a good answer!

Now that I've said my piece, I apologize for the rude response above.

Normally, the materials found in an air gauge that can handle water will also be okay with alcohol. Metal and most plastics will handle both. The black rubber sealer should be good also.

-Deerslayer

Guage or no guage, I'm going to get one of them 5425's for my 3/4 acre, use it for 29 days and then get my money back like KandyKane.

Look for tire gage when pull out scale it will go back in by spring thats one for fluids the spring push fluid out you have to read this gage when on stem acme has them look just like regular gage with slide out scale but spring loaded. Tell husband on big tractor the pressure will drop once the tire goes to rolling by about 3 psi.

I could be wrong, but here is an idea I had. Couldn't a person get a regular pressure gauge like used for air, water, or oil and attatch it to a tire chuck fitting like used with your air compressor? The gauge should have no problem with the water or alcohol, as the insides are made of brass usually. Of course it might be more that the $5 that the link above shows, but it should be easily obtainable.

I just kinda eyeball mine.
Mybad?
That's just the fronts. The all important rear tires have been pumped full of industrial slime. "Is that slime" I asked the guy at the little rural tire shop. "No he said it's better than slime".
That was two years ago and neither back tire has gone flat. We had prickly pear along the fenceline in Springtown, don't have that here. Must be good stuff though.

Nancy: You have committed no crime! Your tire is not full of alcohol, it has only so much alcohol added to the water to keep it from freezing. I guess only about 1/3 alcohol.

Forget this other stuff and measure with the valve STEM UP so there is no water in the area and measure it with a regular tire gauge. The tire should not be completely filled with water, only about 3/4 full with water. If you get water in your gauge you can get it out by checking the pressure in the front tires two or three times. This will blow the water out of your gauge. Good luck and forgive us for being a little harsh.