With thanks to Alvaro Rodriguez, this set is exquisitely 3D CAD designed to accurately represent authentic Firestone tyres and Humber wheel hubs. The same type was used on all versions built on the Humber Heavy Utility chassis - the staff car, the Light Reconnaissance Car, the Scout Car and the Light Truck.
The tread pattern is what sets Alvaro's designs apart. Note the wheels are 'handed' so that the wider part of the pattern meets the ground first. The set is suitable for both 1/76 and 1/72 models.