Does anyone know what Ackerman is?

[Russ]

I've seen a few posts recently about building your own IFS. Anyone considering doing it know what the Ackerman principle is? Do you know how to design it in correctly? Just checking.

[devilbrad]

If you imagine both front tires going through a turn, the inner tire needs to take a tighter circle than the outer tire does so as not to scrub. Ackerman is the principle that when steering, the geometry will allow the inner tire to steer farther (tighter circle) than the outer tire. FWIW I was asking questions about IFS on a very very serious hardcore racing board and was told the original idea of ackerman was to keep the gravel from getting disturbed in rich peoples driveways back in the days and that most race teams dont even bother with it. The most important thing to keep in mind is keep the upper and lower control arms as close to the same length as each other, and make the steering tie rod inner and outer pivots as close to the lower control arm pivot lengths to eliminate bump steer.

[devilbrad]

Oh yeah.....ackerman is achieved by placing the spindle forward or backwards of the imaginary line drawn between upper and lower balljoints. Forward will give more, rear ward will give less, as looking from the side of vehicle.

[Roger]

If you imagine both front tires going through a turn, the inner tire needs to take a tighter circle than the outer tire does so as not to scrub. Ackerman is the principle that when steering, the geometry will allow the inner tire to steer farther (tighter circle) than the outer tire.

Its also more commonly known as toe out on turns. (I think the Hunter Alignment Machine programs refer to it as this). If memory serves me corectly.