Thread: NZ towing laws and practices are making my head hurt, help!!??

Tow bars should come with the weight they are approved to handle, it will be a max weight a downforce weight and usually a Gross Combined Mass for the vehicle they are fitted to.

The downforce is recommended at 10% of towed mass, so a 3500Kg trailer should have 350Kg pushing down on the towball. This comes off the load the tow vehicle can carry so you can't load up the tow vehicle then attach the trailer or you will be overweight somewhere...

The unbraked weight is a NZ road regs rule, aligned with Aussie and it doesn't really matter how the trailer is configured if it's unbraked you are not supposed to drag it over 750Kg (there is a substantial number of tandem trailers without brakes that likely go over 750Kg by themselves without anything on them). As noted, enforcement is haphazard at best and a lot of wof places don't even look at this. I've seen it pulled up once at VTNZ locally, a tandem box trailer without brakes that was 850Kg empty.

Each tow vehicle will have a max towed mass that it can legally pull, although you often need to go back to the manufacturer to confirm this off the chassis number.

Easiest answer especially for boats is to fit brakes, as most boats when full of fuel, gear and fishing rods crack the 750Kg limit. Also, brakes tend to make the ride a lot smoother on the road and this means the hull doesn't get as rough a ride especially with an outboard bouncing on the transom!