Mad Max Gigahorse- looking for tire source-any ideas?

[Ridge Rider]

http://thecredits.org/2015/05/heres-how-they-built-the-beastly-machines-for-mad-max-fury-road/

This is the best reference I have found.  It appears that the rear duels are 72" or 2.88" in 1/25 scale.  The fronts look to be about 48" or 1.92" in scale.      

I have been searching the web but not quite finding what I'm looking for.  Any leads or ideas would be appreciated as would any more reference material.   Thanks, Steve

[Toner283]

Check for places that sell scale tractor parts. A retailer near me has 25-30 different sizes of tractor wheels and tires for restoring toy tractors.