3 link CMS setup help

[calcagno45]

Working on a AR60 based 2.2 rig. Currently 13" WB, VP CMS mount and 3 link. I'm getting some bump steer when the suspension is compressed to one side. When compressing evenly, very minimal bump steer. I've tried shortening and lengthening the drag link to try helping this without success. I moved the panhard mount further forward in the second video. I have a VP bumper CMS mount to try out as well.

Looking for suggestions to eliminate the bump steer while keeping the CMS.

Quick videos showing the suspension and bump steer
https://youtu.be/MJBVnsgwmYQ
https://youtu.be/0pR5JrhroJo

[willyg1981]

Might be a stupid question but does it do it with the servo powered up ?


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[Brake Weight]

My understanding is that the two links need to be as close as possible to the same path of travel. If they can't be mounted side by side then you'll need to tweak them until they have the same moment/motion/angles/geometry/know what I'm saying. The servo arm moves so to me that one should be based off of the pivot point of the servo itself.

For test purposes. Can you move the fixed link to the far left servo mounting bolt and try the same thing again?

[Rjohn929]

The panhard and the steering link need to be as close to the same length and angle as possible.

[DonsATV]

Panhard Bar Question

[calcagno45]

Originally Posted by willyg1981

Might be a stupid question but does it do it with the servo powered up ?

Not a stupid question. I'll try to confirm and rule it out.

Originally Posted by Rjohn929

The panhard and the steering link need to be as close to the same length and angle as possible.

I did bring the links to the same length at 110mm but the angles didn't change. I'll see what I can to on getting them on the same plane.

[calcagno45]

Originally Posted by DonsATV

Panhard Bar Question

I hadn't found that one. Thanks!

I unscrewed one side of the CMS and rotated the rear of the mount downward. I was able to match up the angle on the drag link and panhard as suggested. I also made sure the 2 links were close on length. This seemed to knock most of the bumpsteer out.

When looking from the top, the links are not parallel. I'll have to move the servo around and get a shorter horn to get the links parallel there as well. I think I'll get it nailed down.