Ball weight refers to the weight on the front end of the trailer not carried over the axles. As a rule you should aim to have 10 percent of the total trailer weight as ball weight. This can be measured at a weigh bridge by resting the jockey wheel only on the scale.
Alternatively Hayman Reese distributors have a Ball Weight scale with which you can measure your ball weight by placing it under the coupling and winding the weight off the jockey wheel.
If your vehicle has a tow rating this can be found in the handbook under the towing section. The vehicle tow rating will include a trailer weight capacity and a trailer ball weight capacity.
All Hayman Reese towbars have a compliance plate which states the maximum tow rating and the towbar ball weight capacity. You should check the handbook to check the details for your particular model.
The towbar must have a capacity that exceeds the loaded weight of the trailer you are intending to tow. Therefore you must check the rating of the towbar and the vehicles rated towing capacity which is included in the towing section of the cars handbook. There are two types of towbar available. For light duty towing generally up to 1250 Kg \'standard\' towbars with a bolt on tongue are used. For heavy duty towing a hitch receiver is used which has a square hole designed for a removable ball mount or the Hayman Reese Weight Distributing Hitch.