3" x 1-1/2" V-Groove Cast Iron Rigid Caster with Roller Bearing caster-type-ductile-steel 400 Hub Length (Plain Bore):

400 Hub Length (Plain Bore): 2-3/16 Wheel Diameter: 6" Hub Length (with Bearings): 2-7/16"

but its hard tread rolls easily and is extremely durable

These wheels also come with thicker treads

7-3/4" x 2-1/2" Flanged Ductile Steel Wheel - Part # 7FL9400DUP

3" x 1-1/2" V-Groove Cast Iron Rigid Caster with Roller Bearing caster-type-ductile-steel 400 Hub Length (Plain Bore):V groove caster wheels are designed to guide equipment by rolling on inverted angle iron track. Elevated track minimizes problems caused by floor debris. The relief groove at the base of the "V" equalizes the load on each face of the angle. When not operating on track, the considerable wheel tread on each side of the V groove allows for use on smooth floors. Cast iron Semi steel wheel offers a strong, resilient, cost effective solution for heavy