About 95% of towballs sold in NZ  are 1 7/8” diameter, and the remainder are 50mm diameter.

1 7/8” is the most common towball size used on vehicles in NZ, while 50mm is standard in Europe.

Please ensure the size towball you select matches the size of coupling you have.

1 7/8" Towball Shank Diameter Options - CM Trailer Parts

• 3/4" Shank
• 7/8" Shank
• 1" Shank

Please Note:
A 1 7/8″ coupling will not fit on a 50mm towball, but the 1 7/8″ towball fits into the 50mm trailer coupling easily but is a loose fit, which is very dangerous and must not be done. 

Each