VP Chassis Mount Servo Kit/ Panhard Kit?

[ZippoMan]

Originally Posted by crawler nut

Mine still steers the same as when I had an axle mounted servo. I'm using a 7954 for now and noticed 0 power loss.

Yeah I have that same servo with 2 Wraiths and both with VP CMS/Panhard kits.

No problems so far and the Rubi-Wraith looks way better.

[hooty481]

I run the level 3 chassis mounted servo for a couple weeks and I think they are a waste unless you are all about scale and then I still don't know if it's worth it.

[ZippoMan]

Yeah Level 3 is a waste!! LOL

[Dostradamas]

I am not implying the cms wont work fine with an adequate torque servo only that the wear & tear on said servo is increased. Once you put 400-500 oz of power in the mix it gets there. I think the heavy weight of my wraith (8#'s +) added to the issue.
I am looking forward to a test with pics or vid tho, this topic could use more clarity for someone trying to decide what they want to do.

[crawler nut]

I don't have pics or a video, but I can tell you that it seems to have no more stress than a servo in the stock location. Still steers with ease when in a bind situation and when the pass tire is at full droop and that's when the servo would see the most stress. But it doesn't effect it at all.

[Dostradamas]

Originally Posted by crawler nut

but I can tell you that it seems to have no more stress than a servo in the stock location.

The laws of Geometry & Physics dictate the servo works harder, servos that work harder wear out faster. It is a consideration most overlook, but hey hookers look best in spike heels even though its killing their feet.

[Harley]

Originally Posted by crawler nut

I don't have pics or a video, but I can tell you that it seems to have no more stress than a servo in the stock location. Still steers with ease when in a bind situation and when the pass tire is at full droop and that's when the servo would see the most stress. But it doesn't effect it at all.

Originally Posted by Dostradamas

The laws of Geometry & Physics dictate the servo works harder, servos that work harder wear out faster. It is a consideration most overlook, but hey hookers look best in spike heels even though its killing their feet.

Both of you are pretty much correct. There is such a minimal difference in the performance when setup up properly that you really can't notice any difference.

Using the CMS is not going to have any measurable effect on your servo.

[Pita]

So install was really easy...except for the fact that those of us that use a battery relocation tray. The plastic front piece of the tray had to be trimmed so the servo can be pushed all the way back to its mounting location.
I did not notice any change in drivability, I do need to program my 7955 though the torque when sitting still pulls the front end down when turning all the way to full lock...the truck actually nods at you ill try and get a vid up.

Here you can see the back of the servo touching the trimmed edge of the battery plate.

Here you can see the 7955 tucked up nice and tight.

Front overall view

I stopped by the my LHS and they had all the Robinson Gears in stock too so I thought ah what the hell why not. Very easy install as well.

[wheelhead4x4]

Looks nice an neat. Wishing I had the $$ for it all too.

[ZippoMan]

You will get that nod effect with the CMS/Panhard. I get it too when turning and not moving forward. Sitting on carpet and turning left & right it nods but that is normal. Saying hello!! hahahaha

[kakachille]

gears look beefy

[Harley]

Originally Posted by Pita

So install was really easy...except for the fact that those of us that use a battery relocation tray. The plastic front piece of the tray had to be trimmed so the servo can be pushed all the way back to its mounting location.
I did not notice any change in drivability, I do need to program my 7955 though the torque when sitting still pulls the front end down when turning all the way to full lock...the truck actually nods at you ill try and get a vid up.

Since you are not using high steer knuckles you need to lower the panhard link in the axle mount to the other hole. That should help your bump steer effects.

[Salojac]

Originally Posted by ZippoMan

You will get that nod effect with the CMS/Panhard. I get it too when turning and not moving forward. Sitting on carpet and turning left & right it nods but that is normal. Saying hello!! hahahaha

That nod means something is not set up right. i just insatlled this set up and you can minimize or eliminate the "nod" if you adjust the drag link and panhard to be the same length and same angle. The picture above in this thread is an example of an incorrect set up. These are tips that worked for me. I found them all mentioned here on this forum. I have no binding or forced compression "nodding" at full steer:

1. make drag link and panhard link same length eye to eye.
2. make sure drag link and panhard link are at the same angle reletive to the axle. if you dont have high clearance knucles. I dont. move con rod up and use spacers to get optimum angle.
3. Power up set steering trim to 0. Then adjust servo horn a spline and/or link end to get steering aligned.

Will try to get pics up. Later.

Really happy with this set up.

[ZippoMan]

I said with mine on the carpet just sitting still "nods"....totally normal even with the axle mounted servo. There is just too much resistance from the tires and carpet contact. When moving and not so much on carpet it is fine...hehehe. I just wanted to test my Wraiths with the CMS/Panhard and the one I have without on my carpeted hobby room floor.

Yes you can help get rid of the majority of "nod" by doing all the suggestions.

[Salojac]

I hera ya man. Didnt mean to ding you, sorry if it sounded that way.

Some more observations:
-you can use the two drag link mount locations as Harley suggests to get angle right.
-This set up seems to be best for wraiths that ride high for crawling. panhard/cms with a droop set up does not appear to be a good combo. I have not run it yet but I will try it to find out.

[Salojac]

I now have the vp cms panhard and l3 droop kit installed. Have run the rig on both rocks and flats.

Rocks: As I suspected the panhard with droop set up limits front travel quite a bit because the panhard contacts the axle truss very soon when both shocks are compressed. This is offset by the fact that articualtion is not that bad, although more limited on the drivers side. The rig was still able to crawl OK but not great because the rear is unobstructed.

Flats: Now...for going fast, droop is great. I am set up for speed right now and the rig handles it well becasue its so low to the ground. I can drift on loose surfaces at speed rather than just flipping over all the time.

Conclusion: I am not convinced that the CMS/panhard with droop is a great idea if you want to crawl on bigger rocks. Its good for medium trails and bashing around the park. I am going to enjoy the speed for a while but I think the wraith is best suited for going a bit slower and being good at tackling the bigger stuff. I think I am going to keep the cms/panhard but raise it back up and slow down.

[evan03]

Not sure why the servo would work harder.

I do know steering geometry will change with articulation the pan hard is keeping the axle from pulling or pushing on the servo horn.

I've been going back and fifth for awhile about doing the cms or not.

[Dostradamas]

Originally Posted by evan03

Q. why would the servo would work harder?

A.steering geometry will change with the articulation of the pan hard

Steering geometry does not change on an axle mount with articulation.

The variable geometry means there is variable leverage/force the servo must deal with (thus works more)

As Harley stated it is a really insignificant amount of difference that most will never notice.

I am a cheap, picky ba$#erd & good servos are not cheap, so I want to help it stay alive any way I can.

I think it comes down to competition or aesthetic choice, if you scale comp CMS gives you scale points & if you like the look better than who can argue with that?
I don't scale comp or care what it looks like, if it works!
Dinky s mount is easier to dial in with no bump steer ever (also adds weight to the AXLE, not the chassis)
The dinky mount also replaces the axle truss & adds tremendous strength across the center of the axle.
I am running plastic axle cases with Steel Beef tubes so I wanted more strength & weight down low, If I was running AL axle cases this would be less of a consideration
CMS w/panhard demands a tight accurate setup for no bump steer.
The VP CMS / Panhard is the only drop in I have seen I would buy / use if I was scale compin

[evan03]

Now that I've got a decent servo I may tackle a custom cms build. I wanted to do it but wasn't having any luck coming up with my own pan yard mount on axle. I've recently been giving some ideas and will relook at the cms. My wraith is low so if I can get pan hard and steering fairly level with little to no limit on articulation it should be doable. I know on my 1:1 rig the cross over steering works well and isn't steering from the center. Maybe this is what's needed to work correctly. Long pan hard and steering

[Dostradamas]

Originally Posted by evan03

Now that I've got a decent servo I may tackle a custom cms build. I wanted to do it but wasn't having any luck coming up with my own pan yard mount on axle. I've recently been giving some ideas and will relook at the cms. My wraith is low so if I can get pan hard and steering fairly level with little to no limit on articulation it should be doable. I know on my 1:1 rig the cross over steering works well and isn't steering from the center. Maybe this is what's needed to work correctly. Long pan hard and steering

Make sure your panhard link & steering link are the exact eye to eye length as the drag link & at the same angle relative to the axle.