What is steering Ackermann?

My top diagram is a simple version of the top pic on Havoc's post above. If you re-read my first post and see that "R" is the center of the rearend, "A" and "B" are the bottom balljoints and all three create the triangle that is shown by the dotted line on Havoc's post, the angle "RAB" is the angle you use to figure out your inner tie-rod points.

Does that make sense?

It does now Max! I was lost through out this whole thread until you made that last statement.

Good Lookin Out Brotha!

got it!!

If you know some trig (sine, cosine and tangent) you should be able to calculate the correct angle needed at the tierod. If you don't know that math, you will need to draw it out and find it with a protractor.

A center link is fixed to the frame, spindle to the suspension then the tie rod connecting it all...add some roll and suspension travel in there this will never be perfect. But yeah i could see setting a ride hieght, running some strings, taking some measurements and putting the trusty pythagorean theorem to use getting you close.

Originally posted by lobdyblazr



A center link is fixed to the frame, spindle to the suspension then the tie rod connecting it all...add some roll and suspension travel in there this will never be perfect. But yeah i could see setting a ride hieght, running some strings, taking some measurements and putting the trusty pythagorean theorem to use getting you close.

I think that you are underestimating the ability of a good designer. There is no reason that you could not build a suspension that has minimal camber change, NO bumpsteer issues, NO caster issues, NO ackermann issues and a desireable scrub-radius. If you aren't trying to accomplish one specific job (perfect handling, or a good launch off the line for instance) there is no reason at all to have any real issues.

^^^ proven once again why I this guy!

The Ackerman steering compensation provides a way for a vehicle to turn without the front wheels scrubbing.

In layman's terms, this means that when the vehicle is steered in either direction, the inside wheel shall always turn sharper than the outside wheel.

Let's look at this with an example: Say that a vehicle can turn around a 15-ft. circle. This means that the outer tire is pointing at a particular angle that follows the 15-ft. circle. However, the inside wheel, which tracks 32 inches closer to the inside, must turn at a sharper angle so that it can follow a 9.5 ft circle. Obviously, if both wheels turned at the exact angle, they would scrub when the vehicle turns. Not only would this wear out the tires, it would also cause the vehicle to drastically slow-down during cornering.

Although Ackerman steering compensation is a requirement, it can make the steering sensitive, leading to over-steering at high speeds. As a way to make the steering less sensitive, an Anti-Ackerman is used. An Anti-Ackerman is actually a partially compensated Ackerman implementation and allows a small amount of scrubbing when turning. Although this Anti-Ackerman slows the vehicles into corners, it does allow the vehicle to sustain faster speeds without steering instability.

WebCzar's post is getting a bit deeper into the subject than I had expected this to go. His post states that Ackermann is a requirement, that is not at all true, the 2nd gen S-10's have a small amount of anti-ackermann to help eliminate oversteer issues. To have or not to have ackermann is not the problem. Imagine having zero ackermann, both tires would turn into the corner an equal amount (like most of us assumed happened until we heard about ackermann) there would be only a small amount of tire scrub that would be quite tollerable and at high speed would even be neglegible. Or you could have ackermann (like we have been talking about.) Now the real reason that I started this thread, Imagine the outside tire turning more than the inside tire (try it with your hands) The vehicle would lilteraly "climb" itself. If it was bad enough, you wouldn't be able to even drive the vehicle around the block.

I have noticed that there are quite a few of you guys building your own front suspension and the few of you that have asked me to look at your ideas before you get started have all built yourselves into a corner, where even zero ackermann is impossible to achieve without a complete do-over. I just wanted to make you all aware of the fact that it exists and designing your own front suspension can get tricky.

huh...are you a mechanical engineer? or just learn this on your own cuz my head hurts.