Robart scale wheel with rubber tire and aluminum hub with bronze bearing. Can be used for e.g. the P-51 etc. Robart Tire has a tough outer skin, softer inner core and a low bounce design.

Diameter: 4" (~100mm);  Width: 1 1/4" (~32mm); 
Axle: 1/4" (~6.35mm) ; Weight: ~130g

Diameter: 4.5" (~112mm);  Width: 1 1/4" (~32mm); 
Axle: 1/4" (~6.35mm) ; Weight: ~150g