Trailer Nose-Weight After Loading
You drive a category B car with a braked single-axle trailer. The car's maximum permitted towing mass is 1,300 kg and its maximum permitted vertical load on the tow ball is 75 kg. The trailer's maximum technically permissible mass is 1,400 kg, but you load it to 1,150 kg total. You distribute the cargo so that the trailer's own drawbar load is 95 kg. The tow bar on your car is rated for 75 kg. You are about to leave for a 300 km trip on mixed roads, including a stretch of motorway at 120 km/h. The car's rear axle is already close to its limit because of passengers and luggage in the boot.
1. Is the combination legal and safe to drive as loaded? Explain the limits that apply and what you must change.
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No. Two limits are breached. First, the trailer's actual drawbar load (95 kg) exceeds the car's tow-bar rating (75 kg), which is the binding limit here - the car's own maximum vertical load is also 75 kg, so 95 kg is over on both counts. Second, the trailer's total mass (1,150 kg) is under the car's 1,300 kg towing limit, so mass itself is fine, but the vertical load is not.
You must redistribute the load: move heavy items rearward of the trailer axle until the measured drawbar load is at or below 75 kg, ideally around 50–70 kg to keep the combination stable without overloading the rear axle. Re-check the car's rear axle load afterwards, since passengers and boot luggage already use much of it. Only then drive. An overloaded tow ball also unloads the front axle, reducing steering grip.
2. Why does an excessive drawbar load matter more on the motorway stretch than on a slow urban road?
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At 120 km/h the combination is far more sensitive to weight distribution. An over-heavy nose lifts the front axle, so steering feel and grip drop exactly when small corrections matter most. It also raises the risk of snaking: the trailer's inertia can start a lateral oscillation that the driver's steering then amplifies. Braking distances grow because the rear axle and tyres are overloaded, and the trailer's overrun brake may apply unevenly.
At low urban speed the same overload is still illegal and still wears components, but the dynamic consequences - loss of directional stability and amplified sway - scale strongly with speed. The safe answer is not to slow down and continue: the load must be corrected before the trip.