Can servos be too fast?

creasy

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I'm new to the hobby, and currently theorycrafting a Kraton EXB build.

Looking at servos, the default 15kg arrma one you would find in the Kraton 6s for example, moves at 0.14sec at 7.4V.
I've been eyeing a Power HD S25 (http://www.chd.hk/Product_Detail.aspx?id=186) that I can get a really good deal on, but it moves at 0.06sec at the same voltage, would this be way overkill? Judging by the other EXB builds I've been watching online, 25kg torque seems to be an alright fit.

Another thing I noticed, is that the servo spline is not mentioned, and I'm fairly certain the EXB comes with a 25T spline. RCSparks ordered a spektrum servo (6250) that was 23T if memory serves, and that didn't fit. I've tried googling, but can't seem to find any info.

Recommendations or tips are very welcome as I'm still learning the ropes :)
 

jkflow

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That is a typo, there is no 0.06s capable servo in this pricerange, if at all. Search the web for your model and look at the real spec. It's 0.14 as well.
If there is a 0.06s servo with same pricetag please let us all know ;)

The faster the better, there is no such thing as too fast.

Go with the DSServo. I had 2 power HD, one blew it's main gear, the other blew smoke. Not very impressed to say the least.
 

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That is a typo, there is no 0.06s capable servo in this pricerange, if at all. Search the web for your model and look at the real spec. It's 0.14 as well.
If there is a 0.06s servo with same pricetag please let us all know ;)

The faster the better, there is no such thing as too fast.

Go with the DSServo. I had 2 power HD, one blew it's main gear, the other blew smoke. Not very impressed to say the least.
Looks like the specs are correct. All the online store that sells it has the same specs.
https://www.rcmart.com/power-hd-ssr...gears-digital-servo-red-storm-s25-rd-00086390

https://www.mibosport.com/en/power-hd-s25-red-0.06s-25.0kg-7.4v-brushless-servo

https://speedyrc.com.au/products/power-hd-s25-0-06s-25-0kg-7-4v-brushless-servo

@creasy If i were you, I would pick it up (depends how much cheaper though) I love fast servo's.
Im using a JX Servo BLS-HV7132MG with a transit speed of 0.07 @ 7.4v and I got it for $50
 
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jkflow

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Fair enough , the OP link isn't working and I went by PowerHD 25kg, which I had myself, my bad.
If you have ~$130 to spend on a servo for a basher, more power to you (y)
Keep in mind that this is a basher and you will burn or break servos eventually and at $$$ that is a bit risky. I still wouldn't get PowerHD based on my experience but YMMV.
 

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That's very high spec servo for bashing! It's probably intended for racing and may not be waterproofed. I bet the price is steep too but will undoubtedly be a fast and strong servo. Your call!
 

suchtragedy

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I have a ds3225sg (25kg) in my infraction that I've been pleased with, it's pretty quick (0.07s @7.4v) and was only 35 bucks on Amazon. Some guys warned me that they tried this servo but they ended up with dead spots in them early on but so far I haven't had any issues and have about a dozen packs ran through mine since it was installed. Main reason the ds3225sg model dsservos are faster is because they use a digital coreless motor where the ds3225mg versions are digital cored motors. The top of the line speedy servos like the one you listed will be brushless motors and those will be more spendy but will probably last longer than coreless motor servos.

We'll see how well mine holds up over time, but I felt confident enough that I'll be trying the 35kg version (0.11s @ 7.4v) in my EXB once it arrives. If it fails me I'll probably invest in something with more heft in it.
 

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Yas

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I have a ds3225sg (25kg) in my infraction that I've been pleased with, it's pretty quick (0.07s @7.4v) and was only 35 bucks on Amazon. Some guys warned me that they tried this servo but they ended up with dead spots in them early on but so far I haven't had any issues and have about a dozen packs ran through mine since it was installed. Main reason the ds3225sg model dsservos are faster is because they use a digital coreless motor where the ds3225mg versions are digital cored motors. The top of the line speedy servos like the one you listed will be brushless motors and those will be more spendy but will probably last longer than coreless motor servos.

We'll see how well mine holds up over time, but I felt confident enough that I'll be trying the 35kg version (0.11s @ 7.4v) in my EXB once it arrives. If it fails me I'll probably invest in something with more heft in it.
Just a heads up with the 35kg - I have it in my Maverick Timberwolf SC truck. It is extremely fast on both 6v and 7.4 BEC and although it does have a lot of torque (probably around half of what it states but still) I did find it had trouble centering - sometimes badly! A German YouTuber unboxed his and after trying it out he found he had the same problem too. I've chosen to keep mine in until it dies. Perhaps you might have better luck with it if you try it, but that's my experience with it 👍
 

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I’ve never understood the fascination with how fast a servo is when bashing or why it’s desired.

I built and raced 1:1 cars for 2 decades and smooth but accurate input is what you always focus on to keep from upsetting the chassis and scrubbing unnecessary speed. The last thing you ever wanted to do was saw at the wheel as fast as possible unless you were attempting to put heat in the tires at low to moderate speeds and you had an extremely small window to accomplish the task.

Can someone give me an example where lightning fast full lock situations are needed off road? I feel like this is just another example of blindly following others without question.
 

olds97_lss

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I’ve never understood the fascination with how fast a servo is when bashing or why it’s desired.

I built and raced 1:1 cars for 2 decades and smooth but accurate input is what you always focus on to keep from upsetting the chassis and scrubbing unnecessary speed. The last thing you ever wanted to do was saw at the wheel as fast as possible unless you were attempting to put heat in the tires at low to moderate speeds and you had an extremely small window to accomplish the task.

Can someone give me an example where lightning fast full lock situations are needed off road? I feel like this is just another example of blindly following others without question.
Offroad, I don't see much point either, but after watching onroad racing... I can't even watch fast enough to see those guys drive and cut around the apex's! Guessing they run pretty quick servos.
 

creasy

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I’ve never understood the fascination with how fast a servo is when bashing or why it’s desired.

I built and raced 1:1 cars for 2 decades and smooth but accurate input is what you always focus on to keep from upsetting the chassis and scrubbing unnecessary speed. The last thing you ever wanted to do was saw at the wheel as fast as possible unless you were attempting to put heat in the tires at low to moderate speeds and you had an extremely small window to accomplish the task.

Can someone give me an example where lightning fast full lock situations are needed off road? I feel like this is just another example of blindly following others without question.
I think you have misunderstood my post. I am not asking because I think faster servos will be better, I ask because I'm unsure how it a high-speed servo affects the car, and if it is plausible to put this servo in a Kraton EXB. It was not picked because of its speed, it was picked for its pricing point and its torque. It certainly has nothing to do with "blindly following others without question".
 

suchtragedy

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I’ve never understood the fascination with how fast a servo is when bashing or why it’s desired.

I built and raced 1:1 cars for 2 decades and smooth but accurate input is what you always focus on to keep from upsetting the chassis and scrubbing unnecessary speed. The last thing you ever wanted to do was saw at the wheel as fast as possible unless you were attempting to put heat in the tires at low to moderate speeds and you had an extremely small window to accomplish the task.

Can someone give me an example where lightning fast full lock situations are needed off road? I feel like this is just another example of blindly following others without question.
The only vehicles I am running semi faster servos in are ones equipped with AVC (Infraction) or gyro (EXB experiment) with the theory being faster servo is better to keep up with steering correction signals. Other than that anything under 0.14s/60° is generally fine for bashing, imo.

The only example I can think of where fast full lock speed makes a huge difference in off-road is in competitive crawling where faster steering speed means more precise corrections while going over obstacles.
 

Mr.Duke

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I think you have misunderstood my post. I am not asking because I think faster servos will be better, I ask because I'm unsure how it a high-speed servo affects the car, and if it is plausible to put this servo in a Kraton EXB. It was not picked because of its speed, it was picked for its pricing point and its torque. It certainly has nothing to do with "blindly following others without question".
My apologies. 👍
That post was not intended to be pointed at yourself specifically, but more of a conglomeration of posts throughout the community over time and from what I’ve noticed throughout various threads on the forum.
 

Yas

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I prefer a quick servo. It helps shift the weight of the car from axle to axle quickly so I can kick out the rear end to drift... I pull off mad Scandi flicks with my SCT 😂

In my Noto I use a 1210SG at 7.4v and I've found it's speed helps in emergencies such as when turning whilst braking to avoid having a crash, or for tight corners like hairpins... although tuning the diff oil weights helps most with this

I think I would prefer a quicker servo over one that favours torque, as some of the torque is wasted at the servo saver anyway. I guess this all depends on what tyres and surface you're running on!
 

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I have ran flagship servos, and was one of the first to praise the Amazon special DS3225MG WP. In the end I settled on the Savox s1211sg. Why not the 1210sg? Well specs wise the 1210sg is neither fast nor "torquey" on the stock esc. On 8v the 1211sg puts out more torque than a 1210sg on 6v and remains a fast servo guaranteed to be waterproof 👍. However, I really do feel theirs value in the $150+ servos, the gains are minimal, but good components will save you $ in the end, it just depends on what's reasonable to you. If you wanna way over do this or that, isn't that fun of the bashing scene, no limits, rules, guidelines. Do what makes you happy.
 

BashingBrian

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For off road, to me torque is far more important than speed..!!

Here’s the servo I’m putting in my EXB when it finally arrives 🤣 bought for torque not the speed.. it’s also smaller, cheaper, and higher spec than any equivalent Savox servo that I know of..🤔

9DCC3C93-8CB1-4584-819C-2D83A1BC79C6.jpeg
 

L3phturn

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I’ve been running these in my cheap 1:10 bashers. I have one ready to go into my Notorious whenever it finally arrives. Do you think these are too weak for a 6S platform?

[CA$17.63 8% OFF]KS-3518 Digital Servo 20KG Waterproof 180° Metal Gear Large Torque For RC Robot Arm RC Parts from Toys Hobbies and Robot on banggood https://banggood.app.link/3LrduCBVA8

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
 

olds97_lss

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For off road, to me torque is far more important than speed..!!
FWIW, there is a point where speed is noticeable even to a basher like me. I have one of those old red cheap ebay special servos that has enough torque to lift a building, but it is slooooooow, and it's painfully noticeable. Power KS3620 20KG. Oddly, it's rated only at 20KG, but I swear, it will break your finger before it stops. Holding torque is ridiculous. It's rated at .20 sec @6V.

So, with that in mind, I'd try and stick with anything faster than .16sec for 60° (typically the range of motion they are rated for).

I had it in my outcast while I waited for my first savox to show up and it made it look like the raminator lumbering around and felt about as responsive.
 

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