6" x 2" Cast Iron V-Groove Wheel Rigid Caster - 1000 lbs. Capacity6" x 2" Cast Iron V Groove Wheel Rigid Caster Cast iron v groove wheels are made for use with inverted angle track but they can also be used to roll on floor tracks, gate fence tracks and flat surfaces. Constructed of cast iron with a 90 v groove, this wheel works well inside and outdoors. Tread: Solid Cast Iron 90 V Groove Core: Solid Cast Iron Bearing: Roller Bearing Rig: Zinc Plated Rigid Caster, 4" x 4 1 2" Mounting Plate Capacity: 1000 Lbs.