OTK Caster angles

Does anyone have a good infographic on the different possible caster angle on a OTK (could be generic to karting as well).
I’ve been trying to wrap my head around reducing caster and the effect of a concentric washer on the bottom. By reading the otk guide you can reduce caster by rotating the top backwards and then for a in between you can put a concentric in the bottom. But what does leaving the top forward and and putting a concentric washer in bottom do.

Thinking something like (numbers just for example and not actual)
Top Forward, Bottom Forward = 100% castor
Top Forward, Bottom center = 75% castor
Top Backward, Bottom Center = 25% castor
Top Backward, Bottom Forward = 0% castor

curious if anyone has such a infographic, recall seeing something similar in a setup guide but cant find it anymore

The Baseline position with factory eccentric is:

Baseline - upper arrow forward / bottom arrow forward.

Increased caster - upper arrow forward / bottom arrow backwards

Decreased caster - upper arrow back / bottom arrow forward.

If you buy the centering pills for the bottom you basically cut in half each of those adjustments in half for a finer adjustment either way.

I’ve personally never found a need to reduce caster from default setting meaning I only touch the top adjuster if I need to change camber.

For caster adjustments I either turn the bottom all the way back or install the centering pill in the bottom. That’s all I ever touch.

When you say “100%” aren’t you referring to the total possible “change” of the caster angle. How is the spindle connected to the frame? Some pictures would help.

what I mean by the % is the pin being in a maximum setting, 0% being the complete opposite. bellow being a snip it from the OTK setup guide. As Andy mentioned above you can add the concentric washer in the bottom, just interested the result of that in each position.
Baseline being both forward, and from what I understand the OTK 401R have a good bit of caster naturally in it.
Correction to my original example. “100%” would be top forward, bottom backwards. would be looking at the different steps in once including the concentric bottom washer.


Top Forward, Bottom backwards = 100% castor
Top Forward, Bottom center = 75% castor
Top Forward, Bottom Forward = baseline or 50%?
Top Backward, Bottom Center = 25% castor
Top Backward, Bottom Forward = 0% castor

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And what does that mean “100%” 100% of what? Top forward, bottom backwards; sounds to me like you’re taking caster out, less caster, what I’m asking is, now what is the caster? Pictures would help, schematics!

George - your updated logic is a good portrayal if you want to put numbers to the different positions. Accuracy of the numbers is arguable but the concept is there if that’s how it helps you think about the changes.

Hmm! If we say that setting A gives 100% castor/caster and setting B gives 50% castor/caster that would imply that with setting A the castor/caster angle is twice that on setting B. It isn’t.

he’s breaking it down in totality of available adjustment, not adjustment angle.

Thanks Andy for understanding my thought pattern :slight_smile: lol. didn’t know the best way to articulate it

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I think your assessment is pretty spot on. With the arrows pointing opposite you will be at max or min allowable adjustment and with one neutral pill you can split the difference. So putting in a Neutral Pill on bottom and eccentric on top can give you either 25% or 75% total adjustable range. In many ways, this is why I like the idea of the Sniper system a little better. It does not require a pill swap the achieve the same results. It’s next on my purchase list.

I would say

Top backward + bottom forward = maximum caster you can get
Top forward + bottom backward = minimum caster you can get

I think you have that the wrong way round.

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Yes, that is the opposite way around.

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Maybe the terminology was wrong.
What I was trying to say is that, when you have the top of the kingpin backward and the bottom of the kingpin forward you have the maximum caster.
But if you talking about the narrow, than it would be the opposite way around.

That’s correct.:+1:

(20 char)

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Yep, that’s perfect. Most people deal with the arrows or dots, but kingpin angle is actually a better way of doing it.

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I have extensive collections of demonstrations showing right front spindle configurations. Caster, camber, kingpin inclination. If anybody’s interested. All done with 3-D CAD/CAM in color.


I am interested. How to have access to it?