I have a 6 foot sidewinder brush cutter that needs tires. Not the drive tire but the transport tires. I believe them to be close to 60 years old and they have been flat for the past 40! They are pneumatic and impossible to keep them aired up. I use it very seldom and it's probably been 10 or 15 years since I hooked it up. 

Anyway, I wanted to use it the other day and even though the tires are heavy enough ply to support the mower when flat after this many years they started to come apart. Does anyone know where to find a laminated tire to replace the pneumatic? It is a 5 bolt 14 inch rim.
TIA, Keith