5x18x8 Spherical Bearing (GEBJ5C) by Avid Racing Concepts is commonly used in the large 1/4 to 1/5th scale vehicles. Check your manual for the correct size for your vehicle if you are not certain.
Specifications
Outer race thickness is 6mm (5x18x8/6).
Bearing Dimensions
METRIC: 5mm (Inner) x 13mm (Outer) x 8mm (Width)
STANDARD: 0.19685" (Inner) x 0.51181" (Outer) x 0.31496" (Width)