Robart scale wheel with rubber tire and aluminum hub with bronze bearing. Can be used for e.g. the Spitfire etc. Robart Tire has a tough outer skin, softer inner core and a low bounce design.

Diameter: 5" (~125mm);  Width: 1 9/16" (~40mm); 
Axle: 1/4" (~6.35mm) ; Weight: ~240g