Why does a trailer sway?
Explore with your child how cargo, axles and towing vehicle affect a model trailer setup.
Trailer balance, centre of mass and axle position
A brief steering input sets the setup swaying. Vehicle and trailer affect each other through the hitch. Sideways tyre forces may settle the movement; with some settings it grows during the observation period.
Cargo changes mass, centre of mass and rotational inertia. Axle position changes lever arms and static wheel and hitch loads. Two axles share the model wheel load; they do not simply double the total available friction.
How does the sway change if we move only the axle group?
Try it together in the lab
- Keep the vehicle and trailer identical in both tests.
- Test with unchanged cargo and speed. Remember the first run.
- Move only the axle group and test again. Compare the curves and largest angles.
An activity away from the screen
Mark two cargo positions on a small toy trailer. While stopped, compare how a light, secured model load changes its balance. The screen tests are not guidance for loading or driving real vehicles.