I vote for tubes, as they provide additional protection against tire deflation. Tire problems always seem to occur at the worst times, often in winter when cold temperatures cause inflation pressure to drop. Moving equipment from a warmer indoor ambient temperature to a very cold outdoor temperature is the usual cause of tire deflation.
Every 10 degree change in temperature results in a 1 degree change in tire pressure. So if I have my rear tires inflated to 10 psi in my heated garage at 60 degrees and I go out to plow snow at 20 degrees my tires could lose 4 pounds of air! 6 psi might not be enough to keep the tire on the rim and could cause a flat tire.
Having the tube will prevent the rim leakage if that should happen. Of course you could pump your tires up to 14 psi and maybe that would prevent a problem. The addition of ballast in a tubed tire might also reduce deflation of the tire because the ballast together with the small amount of air in the tire would take longer to cool down when the tractor is moved form inside to outside.
I have had more problems with the front tires over the years due the additional weight of blower/thrower on the front. Moving snow around can cause side pressure on the tires causing them to leak at the rim if underinflated and without tubes. This is a good reason to have tubes in the front tires as well.
I have put tubes in every tractor I have restored and have never had the problems I used to have without tubes. To me. it's good insurance!
