Ball weight isn't fixed. It's a function of how you pack your van — and getting it wrong is one of the most common causes of caravan sway, tow vehicle handling problems, and damage to your tow ball assembly. Here's what's happening and how to control it.

What Ball Weight Actually Is

Ball weight is the downward force the coupling exerts on your tow ball when the van is hitched. For a typical caravan, it's usually 10% of the loaded ATM — though it varies by van design.

If your loaded van weighs 3000kg, you can expect a maximum ball weight somewhere in the 300kg range. The compliance plate shows the rated ball weight for the van.

Why It Matters

Ball weight transfers directly onto your tow vehicle's rear axle and tow bar. If it's wrong, three things happen:

Too Heavy

• Squats the rear of the tow vehicle, lifting the front and reducing steering grip.
• Overloads the rear axle.
• Can exceed your tow ball download rating or vehicle GVM.
• Affects headlight aim — points lights into oncoming traffic.

Too Light

• Van is rear-heavy and unstable.
• Increases sway risk — especially in crosswinds or when overtaken by trucks.
• Can lift the rear of the tow vehicle slightly, reducing rear-axle grip.

The Sweet Spot

Around 10% of ATM is the conventional target — heavy enough for stability, light enough to stay within tow ball and vehicle ratings.

How Packing Moves Ball Weight

Anything you put forward of the axle adds to ball weight. Anything you put behind the axle subtracts from it. The further from the axle, the bigger the effect.

What Lives Forward of the Axle

• Front boot/toolbox
• Front-mounted spare wheel
• Front gas bottles
• Front water tank (on most layouts)
• The bedroom on a forward-bed layout

What Lives Behind the Axle

• Rear bathroom(Depending on model) 
• Rear bumper-mounted spare or generator slide
• Rear storage areas
• Rear water tanks
• The bed in a rear-bed layout

Real Examples of How Packing Changes Ball Weight

Consider a van with the front boot empty and full rear water tank. Loaded ball weight: say 250kg. Now you:

• Move 40kg of tools from rear storage to the front boot → ball weight rises ~30kg (it gains the load forward of the axle and loses it from behind).
• Empty the rear water tank (60L = 60kg) and refill the front → ball weight rises 30–50kg depending on tank positions.
• Add a 25kg generator to a rear bumper slide → ball weight drops ~25–35kg.

Even modest reshuffles can shift ball weight by 30–60kg.

How to Fix High Ball Weight

1. Move heavy items rearward of the axle — but not too far back.
2. If the front boot is loaded with heavy gear, swap it with lighter items from the rear.
3. Travel with the rear water tank fuller and the front emptier (if you have separate tanks).
4. Move tools and recovery gear to the tow vehicle if you can.

How to Fix Low Ball Weight

1. Move heavy items forward of the axle.
2. Travel with the front tank full.
3. If you have a rear-mounted spare or generator, consider how much it's pulling ball weight down.
4. Avoid storing dense items in the rear bumper area for travel.

How to Measure Without a Weighbridge

A ball weight scale (around $50–$200, available from caravan accessory stores) sits between the coupling and the tow ball, giving a direct reading. Worth owning — it lets you experiment with packing and see results immediately.

Cheaper backyard method: park the van on a level surface, lower the jockey wheel onto bathroom scales (with a piece of timber to spread the load). Crude but indicative.

Signs Your Ball Weight Is Wrong

Likely Too Heavy

• Tow vehicle nose pointing visibly up when hitched
• Steering feels light, vague
• Heavy steering on tight turns
• Headlights pointing high (oncoming drivers flashing you)

Likely Too Light

• Van fishtails or sways in normal driving
• Sway worsens dramatically when overtaken by trucks
• Van wags noticeably in side winds
• Crosswind handling is twitchy

If you experience persistent sway, see Caravan Sway: Causes, What To Do Immediately, and How To Prevent It in the existing help centre — ball weight is one of several factors but a common culprit.

Weight Distribution Hitches (WDH)

A WDH redistributes some ball weight back to the trailer's axle and onto the front axle of the tow vehicle. They can help with high ball weights — but:

• Not all tow vehicles allow them — some manufacturers explicitly prohibit WDH use.
• They're not compatible with most articulating off-road hitches (DO35 etc.). Mars off-road vans typically use off-road hitches that don't accept WDH.
• If your van is sitting at sensible ball weight already, you don't need one.

One Simple Rule

Pack the same way every trip and check ball weight once. After that, just keep the packing pattern consistent. The variables that change trip-to-trip — water, gas, food — should sit close to the axle so they don't dramatically shift ball weight as they fill and empty.

Related: How to Weigh Your Loaded Caravan · Payload Planning: What Really Fits in 500kg · Weights 101