4''&6'' heavy duty sliding gate double bearing wheel 

4" and 6" V groove power wheel Material:  C 45 solid steel Color: Yellow or White Zinc Plated Bolt & Nut:  1/2” for 4” wheel 5/8” for 6” wheel Bearing: Precision ABEC-1 sealed bearing Loading Capacity: 3000 lbs for each 4” wheel 5000 lbs for each 6” wheel Weight: 5 lbs for each 4” wheel 12 lbs for each 6” wheel

Sliding Gate Wheels Nylon Rollers 4" and 6" Power Wheel Door Stoppers European Hinges