In short, its another way of changing Ackermann. The below picture might help, and I’ve numbered the different setting points on my randomly drawn steering shaft.
You can see the path that the mounting points are going to follow as the wheel is turned. If you can imagine just the distance left to right that each setup will travel as the steering wheel is rotated, you can see the outer points (2 and 4) have “more” (if we define more as a bigger difference between the outer and inner wheel) Ackermann than the inner ones (1 and 3). You can see that happen on the graphs below that the outer setups diverge faster than the inner.
Its kind of confusing, but here’s a graph with all the setups. Since this is turning the wheel left, the left wheel will always turn more than the right, which makes it the upper line on all graphs.
Now remember, most of the time we’re not turning the wheel 90 degrees (that ain’t fast), so if you zoom in on the 0-30 degree range you can see why using lower holes on the steering shaft increases steering effort since you’re moving the tie rods more per steering wheel angle.
Good stuff. I almost never adjust Ackermann. And I almost always leave the tie-rods in the bottom holes on the shaft (3). For drivers with fast hands who are constantly over-driving, I move the tie-rods up to (1) sometimes.
On my Birel’s (It may be different on other models) there is no adjustment on the Spindles at all. Ackerman is only able to adjusted on the steering shaft, and if I change it, it is purely a leverage change, ie the holes further from the shaft will make the steering heavier and the ones closest will make it lighter.
The idea of changing the ackerman rate is never considered at all… haha
Maybe I should start some strength training…
Also for anyone wondering
Ackerman - An elegant and simple mechanism to approximate ideal steering was patented in England in 1818 by Rudolph Ackerman, and though it is named after him , the actual inventor was a German carriage builder called Georg Lankensperger who designed it two years earlier.
The Kart Republic’s are the same, 3 options on the steering column, one location on the spindle.
Also one thing to keep in mind when thinkingabout ackerman, you adjust the ackerman when you adjust the steering column height as well. Moving the steering wheel up/down changes the angle the tie rods sit at and affects both the ackerman and steering rate.
