Replacing a TR 218 tractor valve stem

The valve stem on our 190XT has rotted away. It is the bottom part that is attached to the tube.
What are your thoughts on just replacing the vave stem rather than buying a new tube ? The tube is nice and soft and has no patches. It is very pliable etc and looks like new. Where is the best place to purchase a new stem assembly ? Is it a difficult job to do ?
If I end up purchasing a new tube, what type of tube is best ? Regulat or radial. The tractor has bias ply tires on it.
Thank you for any help you can give me !

Sometimes it works ok, sometimes it doesn't. You don't mention any ballast so that may be in your favor if you want to try it. I wouldn't consider it if the tube has had a ballast liquid in it.

You should be able to get a new cement on stem at a tire shop, parts store, or from an online vendor. For a rear tractor tube the stem needs to be the type with a nylon nut to hold it in the rim hole. The stem might need to be ordered as not everyone stocks them. They just cement on (like a patch) in place of the old stem. I suggest getting fresh cement and liquid buffer (to clean the tube after buffing it) along with the stem for best results. If you are not familiar with patching tubes, you may want to reconsider doing this or have a tire shop do it for you. The real work is not in installing the stem, it is in dismounting the tire, removing the tube, proper prep of the tube for the stem/patch then reinstalling the tube and mounting the tire back on the rim. If you slip and install the tube (repaired or new) backwards you will likely rip the stem off.

As for a new tube, the USA made Firestones are about the best currently, bias or radial, from most reports. You should be able to get bias tubes the size you need with no problem. The proper size of either type should work, if needed.

Do you have tools for mounting dismounting tires? Have you done tires like this before? Nothing against your skill sets but your questions indicate to me this will be new ground for you. Do you have someone who has experience to help you? Personally, I wouldn't mess with trying to replace a stem on a rear tractor tire for the work involved, if it doesn't hold. JMHO

Take the tube to a farm or heavy truck tire store. They will have them in stock and instal it for you. A new tube will be around $80.00 so try a new stem.I would expect to be charged $20.00 to $25.00 for the repair.

Got fluid in it, replace the tube with a new radial tube. If no fluid, take a fairly sharp knife, cut the old stem off, buff the tube down good and glue a new stem on. I've done dozens of them, make sure the tube goes back in with the stem on the same side as the rim hole.

If it has fluid in it, replace the old tube with a new radial tube. If it has no fluid in it, simply take a sharp knife and cut the old stem off and glue a new stem on the old tube. When putting the tire back together, make sure the valve stem is on the same side of the tire as the hole in the rim.

Many thanks for all your suggestions. I sincerly appreciate all your help.