If you have a towbar and don’t know how big your towball is, check it out! All towballs have their ball size stamped into the top of the ball.

As you might know, NZ’s most common tow ball size is 1 7/8” (47.625mm). But with the influx of European vehicles coming into New Zealand, along with imported trailers and floats, new tow ball sizes are increasingly 50mm.

That’s a difference in diameter of less than 3mm. But that’s enough to make a huge difference to towing safety!

The difference does result in a lot of confusion. While a 1 7/8″ coupling will not fit on a 50mm towball, the 1 7/8″ towball will fit into a 50mm trailer coupling easily… but is a loose fit, which is highly dangerous – with a real risk of the trailer coupling jumping off the ball on the road.

Towballs and couplings are critical safety components which are engineered to high standards, with very little tolerances or margins for error. The two items form the crucial link between the tow vehicle and the trailer – any incompatibility between the two could have hugely serious consequences, with the potential for a trailer to detach from the tow vehicle and career into oncoming traffic. With that in mind, it is critical the correct pairing is used.

The Smooth Mover offers a range of trailers for hire. And with both safety and practicality in mind, all of our trailers and new double horse float available for hire have clever dual fit tow couplings, which will safely accommodate either a 1 7/8” or 50mm diameter tow ball. The new couplings are super easy to use and require less time to attach than previous couplings.

Contact The Smooth Mover if you’re in need of a trailer this weekend!