4" Heavy Duty Caster Wheel - Cast iron PU - Top Plate Mount Outer Diameter - 1 1/16 inch (1.0625") these are the upgrade your

these are the upgrade your kart needs

6911LLU Ball Bearing

331" inch and Bearing width is 2

6060M bearing is Oil Preservative preserved

NN3012M2KC1NA P5 width is 26mm

4" Heavy Duty Caster Wheel - Cast iron PU - Top Plate Mount Outer Diameter - 1 1/16 inch (1.0625") these are the upgrade your4" Inch Caster Wheel 772 pounds Swivel Cast iron polyurethane Top Plate VXB009100BCPU Heavy Duty Wheel Diameter= 100mm Wheel Width= 50mm Wheel Diameter= 4" Inch = 100mm Overall Height= 124mm Overall Height Inch= 4. 882" Mounting Type= Top Plate Top Plate Size= 138mm x 110mm x 10mm Hole distance= 110mm x 75mm Wheel Core= Cast iron polyurethane Tire= Cast iron polyurethane Bearing type= Precision double ball bearing Load Capacity= 772 lb Mounting=