How to prevent a trailer from fishtailing / snaking / jacknifing


What is jackknifing?


Driving with a trailer is higher risk than without, and occurs when the trailer starts moving from side to side.

The causes of a “snaking” or jacknifing trailer can be heavy winds, especially with bigger trailers and caravans, uncontrolled speed

Unevenly distributed weight in the trailer

Incorrect balancing on the trailer


Trailers that start fish-tailing on the road can be dangerous and even flip the vehicle causing a serious and possibly fatal accident.


Avoid jacknifing a trailer:

There are two essential factors when trying to avoid a jacknifed trailer.

These are speed and packing of the trailer.


Packing a trailer to prevent jacknifing:

  • Pack the trailer correctly – with the heaviest items in the front, and then distribute the items evenly through the trailer. The weight needs to be distributed like this to prevent extra weight on the hitch.

  • Don’t over-pack the trailer, use the specifications that are set on the trailer.

  • The trailer should always be level.

  • Packing weight should be around 60 % in the front section, evenly distributed, to 40% at the back.

  • Ensure the tyre pressure is correct,


 Being aware of your speed while driving with a trailer to prevent jacknifing:

  • Drive slowly with the trailer, and avoid racing with the traffic, especially slow down driving down hill.

  • Use the same gear going downhill as you would to go uphill.

  • Slow down when stating to go downhill.

  • Try not exceed 70km per hour.

  • To slow down, rather use gears and down grade doing a gently slow-down.

  • Leave 4/5 seconds distance between yourself and the vehicle in front of your, the faster you are travelling, the more the time should be.

  • Be aware of other traffic, when passing a slower vehicle, give space for your car, and twice the trailer when passing another vehicle.

  • Only pass when there is plenty of room to do so safely.

  • Ensure the trailer lights are in working order, with the electrical connection in place on the towing-hitch.

When the trailer starts to sway/swing from side to side:

Take your foot off the accelerator

Never slam on brakes once passing a vehicle to prevent them rear ending yourself and the trailer.

If the trailer starts to snake along the road, don’t put the brakes on.

Gear downhill

Put on the hazard lights – ask person in the passenger seat to do this if you have a companion

Keep steering in a straight line

Move into the slow lane where possible once trailer has stabilised

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