SCX-10 steering Question...

[mmbackpacker]

I am running scx10 axles on my scaler that is nearing it's "completion".... but I am stumped on getting my steering working correctly.

VP 8* nuckles and C-hubs, as well as VP Ti steering rods.
Level3 CMS kit (pushed back along the chassis frame due to shortened wheelbase, but I am 99.9% sure that is not causing anything wonky...)
Axial CVDs
Hitec servo with aluminum horn
Spektrum DX3R

So I am able to get a full throw of steering when turning left, but not to the right. With the tie rod unbolted the servo throw appears to be equal left and right, and with the link bolted on it also appears to be equal. Throw appears to be non binding when unhooked from the servo as well...

I have messed with horn angle and tie rod link length, as well as the adjustments for center on the controller. It just occured to me to reset all the adjustments on the controller for this specific rig, but other than that I am out of trouble shooting ideas....

What the heck am I doing wrong?

Thanks!
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[Big Tex]

first off, even though you have cvds, they do have a lateral limit on the steering angle, try checking your end points on the radio sometimes 100%/100% isnt right, mine at the moment throw to throw (right before binding the cvd) is 90%/70% so check on that when you have the chance and make sure the dual rate on the radio is 100%

if that doesnt work, try loosening the kingpin screw where the bushing is top and bottom a few turns and check your steering, if thats the problem take em apart, get some axle grease on a q-tip, smeer it around where the bushing sits in the knuckle, replace the bushing, and use loctite on the screws, tighten until the knucks are hard to turn then back off 1/4 turn to 1/2 turn until the knucks can turn full left and right unbinded, then leave it over night and your golden "thumbsup"

 

[mmbackpacker]

Thanks Tex, I'll check the endpoints. It is not binding, without the servo connected it throws full lock both left and right, smooth as butter.

I am thinking it is link geometry and/ or electronics.

 

[mmbackpacker]

Well, I am not sure why the videos aren't showing up....

I adjusted the endpoints on the old DX3R (I hate the rolling selector switch!), and it is now doing much, much better. I still can't quite get 100% throw to the right, but it is now 95%+ there, so I'll live with it. Turns like almost like a dream now with the extra radius (thanks VP!) and the U/D gearing (thanks Axial!).

That said, any other ideas about what I am doing wrong?

 

[Big Tex]

Try one tooth over on the servo horn bud, then you should have equal left to right.

Sent from Outerspace Using My iFreeze Ray Gun

 

[mmbackpacker]

Try one tooth over on the servo horn bud, then you should have equal left to right.

Sent from Outerspace Using My iFreeze Ray Gun

Already tried that... All it does is throw the alignment off and then when it is recentered it still doesn't turn as far right as it does left... Leading me to conlude it is link length ( the link goes from the servo to the right side)

Thanks again Tex, good ideas.

 

[Charlie-III]

Already tried that... All it does is throw the alignment off and then when it is re-centered it still doesn't turn as far right as it does left... Leading me to conclude it is link length ( the link goes from the servo to the right side)

Thanks again Tex, good ideas.

Just so I'm clear, when all assembled, the servo does not swing as far L/R as it does with the steering link off??

Is it possible a link or nut is hitting something causing a bind?

It is possible, due to steering geometry, to get to a point that the servo can swing but the link pivots don't allow more movement.

 

[Manning]

It's the geometry. Mainly due to the Ackerman built into the knuckles.

You'll have to juggle the link length AND initial servo horn position (like tex mentioned).

So, move the servo horn over one tooth (or sub trim on the radio, but not regular trim) so the horn and the knuckle arm that the drag link attaches to are close to parallel, AND make the drag link longer so the wheels point straight again. that should do it.