You might not have heard of “Ackermann Angle” but every time you turn your car’s steering wheels you experience it… and we’re not talking about that sticky substance left on the tiller after a midnight run to Macca’s.

The Ackermann principle at its simplest means the inside wheel always turns on a tighter radius than the outside wheel. First patented in 1818 by Rudolph Ackermann, the Ackermann geometry is actually a theory describing steering linkage angles that increase the turning radius of the inside steering wheel, improving the turning circle and eliminating having front tyres slipping sideways when following a curve or bend.

Perfect Ackermann geometry follows a line from the steering pivot points, ball joints (or king pins) down to the centre of the third-member (also known to you cool kids as a “diff”). When you look at the diagram from above pay particular attention to how the steering arms angle either outwards (on a front-steer set-up), or inwards (on a rear-steer set-up). This is why you can’t simply swap steering arms from a rear-steer to a front-steer set-up, or vice versa.

Ackermann tells us the steering arms on the front hubs need to appear to toe out as the steering angle increases. This allows the car to turn in a tightening radius, improving low-speed manoeuvrability and turn-in response.

If this steering angle isn’t taken care of, you’ll end up with a car that scrubs its tyres and pushes its front-end through carparks or slow-speed turns. And that is pretty much next to un-driveable in a street car!

Next week we’ll have a squiz at the three C's (Camber, Caster and errrr... Toe)