Need steering geometry advice.

[CHawk68462]

This just doesn't seem right to me. I recently mounted the servo higher because the nut on the drag link was hitting the main steering link at full compression. Now I get all sorts of weird things happening under compression.

Any suggestions/rules I should follow to figure this out?

Thanks!

[KMW]

Sounds like you are getting bad bump steer. I'm sure the CMS experts will give you some good info, but the angle of the steering link looks waaaaaaay to steep to me. I think you want to keep it as close to parallel with the tie rod as you can. You might want to use a longer steering link and connect it to the right side of the truck instead? That would reduce your angle some.

Also, are you running a panhard? I don't see one in the pic. What kind of link setup are you running?

[mitchr97]

Alright. You need to mount your drag link to the passenger side steering knuckle. That will help with clearance, and bump steer

Sent from my crappy concord using Tapatalk 2

[CHawk68462]

The setup is 4 link, no panhard. I'll swap the drag link over to passenger tomorrow and report back.

[Arnel]

why no panhard?

[mitchr97]

Originally Posted by Arnel

why no panhard?

Pan hard binds with the four link. Plus, it's not needed as the four link is triangulated, which doesn't allow axle sway. I have the same set up on my truck. Had a little bit of bump steer, but that it's expected with a cms. By the way, you will need a longer drag link, as the one you are using its too short

Sent from my ZTE V768 using Tapatalk 2

[doublej]

What is the reason for running triangulated 4link with CMS?

[mitchr97]

For scale looks without the headache. Plus then, no need for the pan hard because the axle sway is minimized

Sent from my ZTE V768 using Tapatalk 2

[BuhBoombuh]

Going from y link to 4 link was very beneficial with my cms conversion, just need to run the longest steering link possible. The servo horn is on the driver side and I have the link run to the passenger side. Ill post picture if you want

Mostly for scale looks and keeping the servo off the axle for water clearance

[CHawk68462]

So I thought I would need a longer link. Do I still need to swap sides?

The simple explanation for why I'm running this setup is: it's what the axle housings from GCM were designed for.

[BuhBoombuh]

Keep your servo in the same position and make a longer steering link that goes to the passenger side. You need a long steering link to fix the travel geometry.

Although the level3 CMS keeps the servo flat the design to yours should be about the same, I have a bend in my link for frame clearance when the passenger side wheel in up in the well.

[doublej]

I'm sure GCM didn't mean for it to be used with CMS and a triangulated 4link.
I'm not saying it won't work but its not hard to set up a proper link.

Like everyone else said, get a longer steering link and see how your bump steer is. It will always be there but so long as its small and your links don't bind you'll be fine.

[nersik]

Longer drag link should help. In your case to right knuckle, not left. Keep in mind you want to minimize changes in drag link angle during articulation, the angle itself is not critical.
And why can't you mount it with nut up, screw head down?

[Perkolator]

with the GCM axles it will take a little work to get a panhard on it since you will have to figure out how to attach it to that sweet axle. maybe the wraith panhard mount fits on that axle?

like everyone else suggested, move your steering link over to the other side like pictured. chances are you will also have to put a bend in the link somewhere for max clearance when articulating.

i have also been running CMS and 4-link without any issues for quite a while now. took a bit to get everything properly setup and was a real pain in the ass - but my situation was different as i've got several things that made it more difficult -- front axle pushed forward, clocked c-hubs, hi-steer, CMS, 4-link, etc; but after some tuning i was able to get everything to clear, barely, but it does.

[mitchr97]

Here is my set up. I did the DIY cms,




Sent from my ZTE V768 using Tapatalk 2

[Ty@Tekin]

The panhard is just more scale looking, the CMS 4-link is much easier to do with stock parts and works just as well. I don't really worry about bump steer much at all and I just prefer the panhard for the looks and cool factor. To each his own.

[CHawk68462]

I initially asked about a panhard when I was buying the axles from Chris. He said it would require custom work and ultimately wasn't necessary with the 4 link.

Thanks for all the solid input. I've got lot of great suggestions to work with. I'm trying to get this sorted before the weekend.

This truck was purchased shortly after my dad passed away early this year. My goal is eventually to have a scaler that looks like his 72 Chevy C10. The honcho, as it is now, represents the evolution of my RC knowledge. I'll get to the 72, but for now the Honcho is a great learning tool.

My sister (who has a SCX10 as well,) and I are planning on crawling this weekend to celebrate Dad's birthday. Getting this worked out is important. Thanks all!

[micro racer]

I had something that looked like the first pic a few days ago. Put the bent ball end on the servo side of the drag link. It should help a lot. Not the offset ones like for the tie rod, the bent ones.

[CHawk68462]

Updated geometry. I would really like to put a bend in that drag link, but I'm not sure what do do. There's still a lot of bump steer.

[mitchr97]

I also get a good amount of bump steer, but it really doesn't bother me. Drive it a few times, and see how you like it

Sent from my ZTE V768 using Tapatalk 2