Granite Stock servo and servo saver/horn don’t play nice together.

[Kingofanna]

I got the new Granite 4x4 about two weeks ago. Took it out for the first run and clipped (Barely) a step. The wheels became locked to the left because the tiny plastic splines in the horn and the tiny plastic splines on the servo slipped and repositioned the center. I took it apart and recentered the servo horn and took it back out. The splines were rounded off from the hit and as I drove it slowly slid off of center. I adjusted the trim until it was too much. I emailed the warranty department at Hobbico and just like everyone else, they’re sending me a ads-7m. In the meantime I had ordered 2 servo saver/horns and I put one of the new ones on this morning. Took it out for another drive and same thing happened when I bounced off a root. So, I’m waiting to see if the Metal splined servo will help. Two concerns from my prospective.
1- the plastic saver/horn has barely any depth to the grooves that connect it to the servo, it’d be nice to see them changed so they are a little beefier.
2- I just bought my kids 3 Arrma Voltage RC’s and unless I’m missing something it looks like they have the same setup. Hopefully I don’t have to do a warranty claim on all them as well.
Disclaimer: I do know how to drive, it was just dark and didn’t have much room. My Kraton wouldn’t have even slowed down from the hits I took.

 

[Unusual RC]

Show us some photos of the servo horn and servo!
The ADS-7M is a nice upgrade!
I would wait until it arrives.
My ADS-5 also broke very fast!

 

[Kingofanna]

I could post photos but you can't tell they're stripped by looking at them because the teeth on the inserts that go in the horn are so small. I recentered it today and so far this one hasn't slipped again. Still waiting on the other servo. On a bad note, due to the truck being low to the ground (which I like) I drove from grass to a basketball court and caught a little lip of cement and snapped the shock rod and blew the spring perch along with the shock shield clean off the car. Luckily the perch with shield and the shock rod all come as one part from Tower Hobbies for 5 bucks. Temps are in the 50s here so maybe it's getting to cold to run cars with a lot of plastic. Also I shouldn't drive so far away so I can see what I'm about to run over. Guess it's back to running the Kraton this week.

 

[Unusual RC]

Ok, you are unable to make macro photos.
It still sounds that the horn may have never been locked by the screw enough, or simply got driven off by a massive curb hit.
Had an Axial crawler once with 10kg metal geared servo's and metal splined outgoing axis. Because of the power of the servo the plastic horn could lift off by deformation!

Wait for your ADS-7M servo. It will solve your issues!

 

[Kingofanna]

A1C17592-A9BB-4D87-99C3-B98C1B7F91C7

• Kingofanna
• Dec 3, 2017

Servo Horn insert.

3AFF1AF2-39F4-4172-9DF3-69D3B082E928

• Kingofanna
• Dec 3, 2017

It’s pretty difficult to get a picture of the teeth which is part of the problem. The first time it did it it was stock out of the box so maybe it wasn’t screwed all the way into the servo (I doubt it) but the second time it did it I put it on and it was screwed all the way down short of bottoming out on the servo. If it was a massive hit I would understand it happening but it was pretty light and the stock servo definitely shouldn’t have enough power to ward the horn and make it pop off. I think it’s just an issue of plastic on plastic ( flexing) and more so the splines not being deep enough on the horn insert. The metal geared servo should definitely help with the first part.

 

[Hmann68]

My buddy just picked up a new granite 4 x 4 yesterday and out of the box the servo saver was missing the screw and it slipped off right away . We replaced the screw from his parts box and all was well until the second battery pack when he barely clipped a tree root at half throttle and the servo gears stripped out internally . So he is going to go for the replacement upgrade and I hope it works for him . Also on a sidenote when you purchase this truck check the slipper right away , it was so loose the truck would barely move off the line. But the design is great for serviceability and the truck really handles well although it nosedives when jumping pretty heavily .

 

[Unusual RC]

The ADS-5 has very poor, thin plastic gears internally. I have two stripped lying over here. I can only imagine that Arrma is still mounting them to keep the price low.
But with so many warranty claims they might consider to put the ADS-7M instead.
That is a good servo!

 

[bikerbob951]

@Kingofanna Are you still waiting on your servo replacement? I've got a warranty claim on the stock servo too, and the replacement they are sending (they still haven't specified if it's the ADS-5 or 7M) is backordered until middle of January! If it's the -7M, I'll be willing to wait, but if I'm waiting that long for the stock servo, I'll have to raise a fuss.

 

[Jerry-rigged]

Is the SS for these trucks a round thing mounted directly to the servo?

If yes, both Traxxas and Kimbrough make good servo-mounted SS that can be swapped in. Kimbrough is much better quality - I had the same issue with the Traxxas SS stripping the splines. Never had an issue with the Kimbrough. Tower sells the Kimbrough SS.

 

[Kingofanna]

@Kingofanna Are you still waiting on your servo replacement? I've got a warranty claim on the stock servo too, and the replacement they are sending (they still haven't specified if it's the ADS-5 or 7M) is backordered until middle of January! If it's the -7M, I'll be willing to wait, but if I'm waiting that long for the stock servo, I'll have to raise a fuss.

I'm still waiting, they said the were sending the ads 7-m because the original was on back order.

Is the SS for these trucks a round thing mounted directly to the servo?

If yes, both Traxxas and Kimbrough make good servo-mounted SS that can be swapped in. Kimbrough is much better quality - I had the same issue with the Traxxas SS stripping the splines. Never had an issue with the Kimbrough. Tower sells the Kimbrough SS.

It is. The servo saver insert is in the shape of a rounded off triangle. I'm assuming it's arrma specific. Maybe one of those servo horns with the servo savers would fit on there though.

 

[Jerry-rigged]

From looking at the exploded view, a Kimbrough SS could replace all three of the parts in the SS. You would attach the first like to the Kimbrough.

 

[BlurTheLines]

I have the same exact issue as the OP. Waiting on a response from Arrma (hobbico). I wonder if I'd have better luck getting a replacement servo from Tower? Probably going to try to find a replacement. Hope my horn is still usable.

Should the horn have a screw in the back? Mine did not.

 

[Jerry-rigged]

Kimbrough SS -
https://hobbyking.com/en_us/kimbrough-large-size-servo-saver-with-small-end.html

 

[Hmann68]

I have the same exact issue as the OP. Waiting on a response from Arrma (hobbico). I wonder if I'd have better luck getting a replacement servo from Tower? Probably going to try to find a replacement. Hope my horn is still usable.

Should the horn have a screw in the back? Mine did not.

View attachment 13898

My friends didn't have that screw in it either so he put one in after the servo saver slipped off on the first battery pack and then on the second pack it's stripped all the servo gears out internally so we still aren't sure if the screw was supposed to be there or not .

 

[Jerry-rigged]

If you put a screw in that hole, you don't have a SS anymore. That outer ring is a spring that expands to absorb shock from impacts to the front wheels, and "save" the servo from damage. Lock that ring while using a plastic gear servo, and you are pretty much guaranteed to strip the gears the first time your front tires whack something. If you swap in a good, strong, steel gear servo, you can lock the SS and mostly not worry about stripping the servo.

 

[Hmann68]

Ok thanks! Makes sense now that you mentioned it!

 

[BlurTheLines]

View attachment 13898

So my servo started working again after I took it apart and recentered.

Tonight I took the saver apart completely and found that the splined servo cap triangle part of the saver was completely turned backwards. Thus causing it to be sprung open more than designed to be. It’s like they put the servo cap piece on backwards and forced the horn to be sprung open.

Compare my photo above to this servo horn part photo.

Turned it around tonight. I’ll test it tomorrow and see if this solves the issues I’ve had.

My theory is that it was a new employee on the assembly line putting them together wrong. Which essentially made the servo saver not function at all or at the least cause it to not work as designed. This could cause the servo to strip, skip or burn up the internals.

 

[BlurTheLines]

I am 90% convinced that the backwards saver caused my trim hunting and hard lock issues. I am no longer having to trim out repeatedly while driving. I've only had a chance to run 2 packs through it since, so not a fool proof test. With that said, I do think having it in backwards initially damaged the servo and horn. I have a replacement on the way however it looks like the servo saver and servo (ADS-7m) are both back ordered.

 

[Zillion]

Stock servo and servo saver broke on the second run for me. I tossed a cheap tactic TSX45 in because it's what the shop had on hand and aside from being a little slow it's fine.

Does anyone have a part number for a different servo saver that is a bit better?

 

[chazekxt46]

I put a tsx55 tactic in mine. my saver as put in right.