Kraton K8S servo upgrade

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3x9rtse

3x9rtse

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Arrma RC's
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Sorry guys , probably been talked about a thousand times , I tried doing a search and can't find what I'm asking . My servo is not broken , still works , but after upgrading the ESC/ Motor , like to finish it off with a servo upgrade ( faster / more torque ) .Do I throw my Max 5 BEC to 7.4 and wait til it fries / breaks ? What are some options , cost , direct fit VS. modifications , better speed / torque over stock ? Thanks .
 
The S905 is not a true 1/5 scale size servo. FWIW.

You can run 7.4v to get better power and speed out of it. That according to the specs. below from the Spektrum website.

PRODUCT SPECIFICATIONS​

Size Category: Standard
Torque: 6v is 537.72 @ 7.2v is 555.50
Speed: 6v is 0.20 @7.2v is 0.18

I would not hesitate running 7.4 BEC at all.👍
2 tenths of a volt is not any great deviation.
And that servo is just underpowered for the 8s to begin with for a 30 pound rig. It needs all the help it can get. You can get. 🤷‍♂️
Run it till it wears out, or are just tired of it.
:cool:
 
I say run it high till it stops working..picked up a jx for $44 bucks

Dead band:4μs
Working frequence:1520μs / 330hz
Motor:Core
Operating Speed6.0v :0.15 sec/60°
Operating Speed7.4v :0.13 sec/60°
Stall Torque 6.0v :62 kg.cm
Stall Torque 7.4v :73 kg.cm
Dimensions:65.8X30.2X57.4mm
Weight:200 g
Wire/Color:JR 265 mm/ -Brown +Red S Orange
Bearing:2BB
20210311_143847.jpg
20210311_143911.jpg
 
Last edited:
Thinking of getting the Spektrum servo, S9120BL or S9110BL, waiting for reviews :)
 
Any of the proper 1/5 scale servos will be better but you will need the optional 1/5 scale receiver box/servo Mount. I like the spt 70hv from Banggood. It is rated to 8.4volts and only 45$.
Arrma receiver box:
https://www.arrma-rc.com/part/ARA320553
 
HOSS said:
The tooth count is 18 on that one, I have that one to but I can't find a servo savor 18th horn
Click to expand...
:oops: You know....I was so excited to put it all together I didn't even think about the tooth count. The 17 tooth servo saver horn that came with the EXB fit on it quite fine. Wow. I haven't run the truck yet but I have turned it on and played with the steering and it worked good so far. I guess it will either work or I will find out the hard way that it doesn't when I actually run it. Little oversight there on my part
 
StephenSchandelmayer said:
:oops: You know....I was so excited to put it all together I didn't even think about the tooth count. The 17 tooth servo saver horn that came with the EXB fit on it quite fine. Wow. I haven't run the truck yet but I have turned it on and played with the steering and it worked good so far. I guess it will either work or I will find out the hard way that it doesn't when I actually run it. Little oversight there on my part
Click to expand...
That's good to know I think I will buy the new servo savor for EXB 👍thanks that's why it helps to answer any questions love ARRMA FORUM might have to get some merch
 
HOSS said:
That's good to know I think I will buy the new servo savor for EXB 👍thanks that's why it helps to answer any questions love ARRMA FORUM might have to get some merch
Click to expand...
I ran into the same issue but I solved it like this. I took the round plastic servo horn that comes with the amazon servo and shaved off a little plastic with the grinder then did the Same to the 17t horn that comes with the k8s exb, Jb welded them back to back then took a soldering gun and did my best attempt to plasti weld it as much as I could around the edges and through the little Pre cut holes in the horn the servo provides, this is what I came up with... had to cut away some of the servo housing to make the screws from the chassis line up with the holes on bottom of esc/ servo mounting plate, maybe more work then it’s worth but she works and I didn’t but another servo so you be the judge

image.jpg


image.jpg


image.jpg


image.jpg


image.jpg
 
Go4itrc said:
Looks like it should work. I would get the warranty, it's cheap enough. I got a Hobbystar servo never heard of them. But at least I have heard of Power HD servos.
Click to expand...
Did you ever use the stock one before your hobbystar? Just curious how much better the extra torque is
 
So does anyone know if the spectrum

S9110BL or 9120BL fit with the bigger box? People are talking about using it but it looks like it’s a little too tall.​

 
felony4free said:
I ran into the same issue but I solved it like this. I took the round plastic servo horn that comes with the amazon servo and shaved off a little plastic with the grinder then did the Same to the 17t horn that comes with the k8s exb, Jb welded them back to back then took a soldering gun and did my best attempt to plasti weld it as much as I could around the edges and through the little Pre cut holes in the horn the servo provides, this is what I came up with... had to cut away some of the servo housing to make the screws from the chassis line up with the holes on bottom of esc/ servo mounting plate, maybe more work then it’s worth but she works and I didn’t but another servo so you be the judge

View attachment 132866

View attachment 132867

View attachment 132868

View attachment 132879

View attachment 132880
Click to expand...
Update;
First time I landed wrong on the front wheels it broke the Jb weld and lost steering again, just ordered a new 1/5 servo housing and a servo with the correct amount of teeth to fit the supplied servohorn
 
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