Best servo for the Kraton EXtreme Bash Roller

[Custnam]

Hmm I would still think the 35 would have more strength. I run MMX8S in my Kraton 6S trucks and run my BEC at 7.5v.

I went ahead and ordered one. Ill do some comparing once I have it. Thanks

 

[Stokez]

@jondilly1974 . I was looking into getting the DS3235 and have a question. Comparing the 25kg and the 35kg they both put say Stall torque at 5V is 21kg/cm. Then the 25kg says Stall torque at 6.8V is 25kg/cm, and the 35kg says Stall torque at 6.8V is 35kg/cm. And according to the Firma 150A esc it puts out 6V BEC. So would there really be a difference between the 2 at 6v? The speeds are the same between the 2 at Operating speed ( 5.0V ): 0.15 sec/60 degree. Operating speed ( 6.8V ): 0.13 sec/60 degree.

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The difference in performance would be minimal at 6V- I've had both. For the 10 extra bucks id buy the 35kg and have the option to use it at a higher voltage if you ever change your esc .

 

[Custnam]

The difference in performance would be minimal at 6V- I've had both. For the 10 extra bucks id buy the 35kg and have the option to use it at a higher voltage if you ever change your esc .

Yea. I figured for $30 Id give it a try. No plans on changing ESC, but maybe someday.

 

[Paul777]

I've recent put a JX EcoBoost CLS6336HV in my Kraton and thought it was down of steering power, (done the servo saver circlip fix), so I've actually just bench tested it. My JX at least is only producing 13Kg.cm of torque, against the ADS-15M at 17kg.cm.

The test is done using a 2cm arm, so values need to be multiplied by 2 to give the Kg.cm stall torque of the servos.
The Arrma stalls at around 8.46Kg, so about 17Kg.cm - above it's spec
The JX Ecoboost stalls at around 6.46Kg, so around 13Kg.cm - it needs a higher BEC voltage to be useful

Edit: Just ordered a DS3235 so I'll test that when I get it on Monday and see how it compares

 

[Paul777]

So I made up a better jig that had less movement and allowed greater consistency. Still with a 2cm arm, running from a BLX100 6V 3A BEC

	Reading at 2cm	Kg.cm	Expected	Specs
JX Ecoboost CLS6336HV	8.08	16.16	22	27.8kg-cm at 6.6V, 35.6kg.cm at 7.4v
ADS-15M	8.75	17.5	14	14kg-cm at 6.0V, 15kg-cm at 7.2V
DS3235	11.35	22.7	28	21Kg-cm at 5V, 35Kg.cm at 6.8V
ADS-7M (Arrma 3S)	4.00	8.0	6.5	6.5Kg @6V

Expected values above are from interpolating these specs to get the 6V value, how accurate that expectation is therefore has questions.

So only the ADS-12M is performing to spec. The DS3235 is 30% up on the JX I had in there so I'll try that and see how it copes with high speed running on grass.

 

[L3phturn]

So I made up a better jig that had less movement and allowed greater consistency. Still with a 2cm arm, running from a BLX100 6V 3A BEC

	Reading at 2cm	Kg.cm	Expected	Specs
JX Ecoboost CLS6336HV	8.08	16.16	22	27.8kg-cm at 6.6V, 35.6kg.cm at 7.4v
ADS-15M	8.75	17.5	14	14kg-cm at 6.0V, 15kg-cm at 7.2V
DS3235	11.35	22.7	28	21Kg-cm at 5V, 35Kg.cm at 6.8V

Expected values above are from interpolating these specs to get the 6V value, how accurate that expectation is therefore has questions.

So only the ADS-12M is performing to spec. The DS3235 is 30% up on the JX I had in there so I'll try that and see how it copes with high speed running on grass.

View attachment 119361View attachment 119362

Great test! I'd like to see these tested with a Max6 with 6.0v and 7.4v BEC output. What do you have plugged in for a LiPo powering the ESC?

That CLS6336HV servo is listed as Stall Torque (6.0V): 27.8kg.cm (386.06oz/in) on Banggood.
Dead band: 1μs 1520μs / 330hz
Motor: coreless motor
Operating Speed (6.0V): 0.14sec/60°
Operating Speed (7.4V): 0.11sec/60°
Stall Torque (6.0V): 27.8kg.cm (386.06oz/in)
Stall Torque (7.4V): 35.6kg.cm (494.37oz/in)
Dimensions: 40.5X20.5X40mm /1.59 X0.80X1.57in
Weight: 63g (2.22oz)

I am running the CLS6322 in my son's Kraton EXB
JX Ecoboost CLS6322HV 21KG Large Torque 180° CNC Aluminium Shell Metal Gear Digital Coreless Servo
https://banggood.app.link/ZeHSHIFTXcb
Operating Speed (6V): 0.09sec/60°
Operating Speed (7.4V): 0.07sec/60°
Stall Torque (6V): 17.21 kg.cm (239.03oz/in)
Stall Torque (7.4V): 21.06kg.cm (292.46oz/in)

I'd love to see the cheap KS-3518 tested. I doubt it's as fast as the specs say but it would be interesting to see how it tests out. It would be interesting to see how close this $ 15 servo comes to the much more expensive ones.

KS-3518 Digital Servo 20KG Waterproof 180° Metal Gear Large Torque For RC Robot Arm https://banggood.app.link/e836rxgTXcb
Product: KS-3518 Digital Servo
Angle: 90°*2
Voltage Range: 4.8V-6.6V
Operating Speed(4.8V): 0.09sec/60°
Operating Speed(6.0V): 0.07sec/60°
Stall Torque(4.8V): 18kg/cm
Stall Torque(6.6V): 20kg/cm
Gear: Metal
Bearing: Ball Bearing*2
Weight: About 55g

 

[Paul777]

What do you have plugged in for a LiPo powering the ESC?

I tired both 2S and 3S lipos with same results - I guess the BEC is nothing for the battery compared to powering the motor. I also plugged it into my Kraton BLX185 on a new ZOP 6S and the results where the same too.

It is worth noting that the results are taken after about 1sec of hold. The longer you hold the weaker they all get.

Interesting that Banggood lists the specs for the CLS6336HV at 6V yet the JX site lists the same numbers for 6.6V

I have a CLS6322HV in my Big Rock so might pull that out to test one day if I get bored - I love the speed that it delivers.

 

[L3phturn]

I tired both 2S and 3S lipos with same results - I guess the BEC is nothing for the battery compared to powering the motor. I also plugged it into my Kraton BLX185 on a new ZOP 6S and the results where the same too.

It is worth noting that the results are taken after about 1sec of hold. The longer you hold the weaker they all get.

Interesting that Banggood lists the specs for the CLS6336HV at 6V yet the JX site lists the same numbers for 6.6V

I have a CLS6322HV in my Big Rock so might pull that out to test one day if I get bored - I love the speed that it delivers.

Wouldn't the torque at actual stall time or just before be more meaningful? Basically the torque at which it slows enough to not be responsive? Torque after stall would be much less important than torque required to stall.

Thanks so much for the tests!

 

[Paul777]

Personally the torque I'm interested in is the continuous stalled torque the servo can apply and hold. As that is what you need to maintain a cornering radius on grass etc. The issue I see with my Kraton is huge wide arcs when cornering at speed because the servo is not strong enough to prevent the wheels straightening. (I have adjusted the servo saver so the servo can't open it so that isn't the issue). What I have measured here is not the instant peak readings as I'm not sure the value of peak torque in this application. The readings instead are reasonably repeatable values (probably quoted with too many decimal places ) when stalled.
I just took the DS3235 from cold to see what the differences might be. The peak value recorded when steering was applied quickly was 14kg - so 28kg.cm which is about on spec for the quoted stall torque, but it dropped rapidly and was not repeatable until the servo had been given time to cool. Additionally if you apply the steering more slowly as you typically would at high speed the peak is much lower. So it terms of real world performance I'm not sure how useful those peaks are.

 

[L3phturn]

Personally the torque I'm interested in is the continuous stalled torque the servo can apply and hold. As that is what you need to maintain a cornering radius on grass etc. The issue I see with my Kraton is huge wide arcs when cornering at speed because the servo is not strong enough to prevent the wheels straightening. (I have adjusted the servo saver so the servo can't open it so that isn't the issue). What I have measured here is not the instant peak readings as I'm not sure the value of peak torque in this application. The readings instead are reasonably repeatable values (probably quoted with too many decimal places ) when stalled.
I just took the DS3235 from cold to see what the differences might be. The peak value recorded when steering was applied quickly was 14kg - so 28kg.cm which is about on spec for the quoted stall torque, but it dropped rapidly and was not repeatable until the servo had been given time to cool. Additionally if you apply the steering more slowly as you typically would at high speed the peak is much lower. So it terms of real world performance I'm not sure how useful those peaks are.

I am not sure that a stronger servo is going to solve your problem. That sounds like a handling problem to me and not a servo power problem. What is your diff setup and fluids? Is it the same problem off throttle, constant throttle, and increasing throttle? Does it perform differently on a high traction surface vs. a lower traction surface?

 

[Paul777]

I am not sure that a stronger servo is going to solve your problem. That sounds like a handling problem to me and not a servo power problem. What is your diff setup and fluids? Is it the same problem off throttle, constant throttle, and increasing throttle? Does it perform differently on a high traction surface vs. a lower traction surface?

Not to derail someone else's thread with my issues, but I can see that the car is tracking in the direction of the wheels, the wheels just don't have the power to turn in. Running on wet grass in circles as you increase the speed the wheels turn out and the arc radius increases. Doing the same with my Big Rock you get to the point where either the car rolls or slides out as you would expect. What I see isn't typical understeer where the car isn't following the wheels, and at moderate speeds I can still create power induced oversteer. The turn radius is being limited by the turn in of the wheels rather than the cornering grip the car has. No chance of rolling or sliding it at speed. (Diffs are 60K F, 500K C, 20K R) The issue is more related to speed than surface type.

Edit: Dropped the DS3235 in and it was better - but started opening the saver again, so added a couple more circlips and finally I have enough steering power to initiate a drift on wet grass at moderate speed. It could still use a bit more servo power tbh and the servo saver really needs to EXB spring, but it will do for now.

 

[Stubash]

If you go for savox I highly recommend the 1212 it’s much better than the 1210 while having waterproof abilities

Does this fit OK in kraton ?

 

[flipsim59]

Have you checked this one out? Got it in my Kraton EXB, at 7.2V very fast.

 

[Stokez]

Whatever you guys do stay away from promodeler. Went up in smoke on the first day and the owner sent me a nasty email and told me to kick rocks .

 

[dk3000]

Whatever you guys do stay away from promodeler. Went up in smoke on the first day and the owner sent me a nasty email and told me to kick rocks .

Lacking in info for me to just blacklist the best servo on the market over what transpired. Maybe you can elaborate because I'm bummed you had an ugly experience but why would a servo company randomly tell you to kick rocks?

 

[Stokez]

Lacking in info for me to just blacklist the best servo on the market over what transpired. Maybe you can elaborate because I'm bummed you had an ugly experience but why would a servo company randomly tell you to kick rocks?

I have the email chain and BBB complaint if you like to dive into it. I wasn't going to make a huge post. I'm blacklisting because of my experience. Maybe they have the best servo, I never had the chance to see. Not spending my money with that asshat

 

[dk3000]

I'm interested in what happened yes. 100% up to you if u are willing to show the emails. I'll add I'm not at all disbelieving you in that it went up in smoke. You can pm me what was said.

 

[DarkOwl]

Savox is a waste of money... Your paying for the name, you can get the same performance for less $

The mid range Power HDs or the JX eco boost are great servos. Buy from AliExpress & you’ll pay around 1/2 what Amazon charges

View attachment 99417View attachment 99418

I'm all in on these DS3225 since ~ March'20., no issues. Prior, PowerHD, 1 burned up, 1 bearing under the arm disintegrated, both roughly 6 month of use.

If these DS blow up, I plug in a new one (have a spare). All servos will die during bashing, your choice how much money you are willing to loose. Higher price is no guarantee for survival, just cost more to replace.

I'm a big fan of Power HD since I put the 23kg waterproof one in my Stampede 4x4 2 years. That servo ended up being a dream for $40. I was considering the Power HD 25kg for my new Kraton but perhaps I'll venture out and try the DS3225.

 

[jkflow]

@DarkOwl get the 35kg version for the Kraton and adjust your servo saver to handle more power.
If you do not have an immediate need order them from China for 1/2 the cost.

 

[BasherDad]

@DarkOwl get the 35kg version for the Kraton and adjust your servo saver to handle more power.
If you do not have an immediate need order them from China for 1/2 the cost.

When you say to adjust the servo saver to handle more power, do you mean do the snap ring modification?