Camber, caster, Ackermann

[Doc Sprocket]

if i have my steering arms what happens to the ackerman?

I'm not sure I follow. If you mean what do do if your arms face forward instead of backward, then I have your answer. If you meant something else, please clarify.

If your arms face forward, do the string trick, but extend forwards. What you will end up with is steering arms that point slightly outward and forward instead of the "normal" inward and back that you're used to seeing.

Also, could I put a few strong springs eg. valvesprings on the kingpins for slight suspention?

Yes- There have been some "manufactured" karts that use a similar system. A single valve spring won't give you much travel at all, but you could stack 2 or 3 (or more) to get more travel. You'll have to play around with various springs to see which ones have a good amount of "give". You could even create a progressive rate by combining a softer spring with a stiffer one.

 

[r_chez_08]

Sorry, my brain often thinks faster than my fingers, i meant to say pointing forward.
So where do i extend the string forward to? The same distance away as the axle or to something else?

I think i will try the valve spring idea. I will post a link up when i find some springs.
Rob

 

[Doc Sprocket]

Extend forward far enough to exceed the arms- you still need to have your rod ends centred on the string- you just need to project it forward.

 

[r_chez_08]

http://diygokarts.com/vb/showthread.php?t=12599&page=2
Progress

One question about camber: do I want the top of the kingpins to be pointing towards the back or front of the kart

 

[r97]

I think you are talking about castor, not camber, but anyhow, IIRC the top of the kingpin usually points towards the rear on go karts.

 

[Doc Sprocket]

http://diygokarts.com/vb/showthread.php?t=12599&page=2
Progress

One question about camber: do I want the top of the kingpins to be pointing towards the back or front of the kart

That would be caster- and back, usually about 10*.

 

[r_chez_08]

Sorry yeah caster. Ok I thought it was back, but didnt want to weld it up and find out it was wrong, making my steering worse!
Thanks

 

[jamyers]

Extend forward far enough to exceed the arms- you still need to have your rod ends centred on the string- you just need to project it forward.

OK, but what about a kart like mine, where the steering arms go forward and INWARD? While having the steering spindle way up inside the wheel like that I've got almost zero scrub radius, but those steering arms aren't going to go outward as the wheel and tire are in the way. Is Ackermann being provided because the steering column "pitman" arm is longer than the arms out by the tires?

 

[r_chez_08]

Yeah that ackerman is set up wrong. My pitman arms are inside the wheel hub. They are fairly short. This means that the steering lock is very little. I am going to compensate for this by following the basic principles of leverage and shorten the arm on my steering column. Hope that helps

 

[kaymo]

yours is setup exactly the way mine was. we completely revamped the steering... pedals.. everything. to fix that one you have to setup a reverse ackermann. if you put the right linkage in the left hole, and the left linkage in the right hole on the steering plate, you will get some reverse ackermann... but probably not as much as you need.

 

[Doc Sprocket]

to fix that one you have to setup a reverse ackermann. if you put the right linkage in the left hole, and the left linkage in the right hole on the steering plate, you will get some reverse ackermann... but probably not as much as you need.

No, "Reverse Ackermann" is the PROBLEM. What you are describing is compensating for it.

 

[theo]

You could cut the spindles off and swap them from side to side, add 10 - 12 deg. of caster. Shorten the bell crank and change it from pointing up to pointing down. This will cure a lot of your problems.

 

[jamyers]

So...you're saying my kart has reverse ackermann?? It's at my bro-in-law's place, 30 minutes from here - Imma gonna have to go do some measuring....

 

[Doc Sprocket]

Yeah. It's backwards- a VERY common problem with factory built karts that have forward-facing arms.

 

[jamyers]

Sheesh!

You'd think...but then that's what ya get for thinking...

 

[Doc Sprocket]

Yeah. Don't go there...

 

[jamyers]

You could cut the spindles off and swap them from side to side, add 10 - 12 deg. of caster. Shorten the bell crank and change it from pointing up to pointing down. This will cure a lot of your problems.

Then I'll have the steering rods going right where my feet go, yes/no? I'm really trying to avoid completely re-doing the front end...

 

[Doc Sprocket]

put the right linkage in the left hole, and the left linkage in the right hole on the steering plate,

Then this will help. May not cure it, but is the simplest way to regain some ground.

 

[landuse]

Toystory....should we maybe sticky this thread. It has some really good info that would be nice to have at the top of the list all the time.

 

[kaymo]

reverse ackermann is when your arms are pointed forward, and inward, to a center point that is the same distance to the rear axle from the front axle, forward of the front axle. if you setup this "reverse ackermann" correctly, (again with the left and right crossing over each other) you will get "correct ackermann"

your cart is what mine used to look like. of course its much different now. you can tell the difference just rolling around the shop floor. it was a lot of work but worth it. my pedals are now forward of the rods. it allowed me to design an adjustable brake pedal linkage into the system.