Cornering & vehicle dynamics

The forces in a bend

Centrifugal force pushes you outwards. It grows with the square of the speed: at twice the speed, four times the force. A tighter radius increases it further still.

It acts on what you carry, too: an unsecured load shifts, a tall vehicle becomes unstable and a trailer can jack-knife.

The available grip is shared between braking and steering. If you use it all up braking, none is left for the steering.

The four-phase model

1. Orient and signal: look far into the bend, judge its course.
2. Brake before the bend: all of the slowing down happens in a straight line.
3. Steer steadily: no corrections, no jerks.
4. Accelerate on exit: when the wheel comes back and the view opens up.

Remember: braking mid-bend asks the tyres to work in two directions at once – exactly where grip runs out.

Speed, radius and stopping distance

The safe speed in a bend depends on the radius: the tighter it is, the slower you go.

In blind bends the visible-distance rule applies: you must be able to stop within the stretch you can see. Beyond a bend there may be a stationary vehicle, a cyclist or an obstacle.

Safety reserves instead of the limit

The physical limit of a bend cannot be seen: damp, leaves or gravel shift it without warning.

That is why it pays to drive deliberately below what would be possible. That reserve is what lets you correct when something is not as you expected.

Particular points for motorcyclists

The basic theory also applies to categories A and A1 – and on two wheels cornering technique counts double.

• A motorcycle takes a bend leaning over: the contact patch is tiny.
• Gravel, road markings and manhole covers are especially treacherous when leaning.
• Your eyes steer: look where you want to go, not at the obstacle.
• Braking while leaning can bring you down – slow down before you enter.