It sounds like they filled it with some type of goo so that it doesn't need air. In that case you will indeed find it easier to buy a new rim.OK, I have removed the front rt tire / rim, the rim with the 'hairline crack' with the plan to install one of the new tires supplied with the purchase.
This tire/rim weighs a ton. I am guessing that it is loaded for weight, so I removed the stem from the valve stem and no air escaped. I stuck a 16penny down the hole and it sunk into about an inch some black tar looking soft solid stuff.
So I put stuff down and come here...
My intention was to clean up the rim, put air in the tire, then spray with soap to find a leak. Then weld over the crack to seal. I'm not sure what I've got now.
This gentleman that sold to me was probably guessing what was going on (as far as the hairline crack) and it looks like next step is take it to the tractor shop or somebody that has tractor tire experience.
I was going to say something about that, but he plans to keep it for a while so didn't bother. He may realize that they will work for the purposes he uses them for.I actually like those rear tires, but if they don't give the traction you need, I understand.
I've heard of filling industrial tires with "foam", so punctures aren't a issue. I don't know what that stuff looks like/is. You may not want/need the extra weight up front. Have it removed from both. Seek out an industrial tire shop (ie: skid steer, fork lift, etc...) , and they should be able to help.I stuck a 16penny down the hole and it sunk into about an inch some black tar looking soft solid stuff.