I have two rear finish mowers, both with pneumatic tires (a Land Pride AT2560, and a Befco Cyclone 72" rear discharge). All of the tires have been pulled off the rim and had "bead sealer" used on them when they were re-assembled. Both mowers have one or two leaky tires and constantly roll the tires off the rim if I try to use them when they get low on air. As long as I keep a lot of air in the tires, they do fine.

Good luck,
Kelvin