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Servo speed question

smc-93

Quarry Creeper
Joined
Jun 5, 2018
Messages
466
Location
Blaine
I need to replace the servo in my ~14lb TRX6 after my Reefs 555 died, from just sitting around apparently. I'm looking at the Savox SW2290-SG for the price vs. torque. I would be powering this servo at 7.4V for the torque but would there be anyway to slow the transit speed if I feel it's too fast?

I ran a Holmes something or other direct power servo at 11.1 in my TRX4 for a while but I didn't like how fast the steering was (it has a Reefs ATM as well [emoji52]. Might end up changing it as well)

I'm sorry if this has been explained elsewhere already. I tried a quick search and couldn't find anything and I'm too annoyed with my Reefs 555 to dig more deeply.



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I've never heard of anyone wanting to make a high torque servo even slower. What is it about a servo that would feel too fast? If you want it to steer slower... then... steer it slower.
 
I've never heard of anyone wanting to make a high torque servo even slower. What is it about a servo that would feel too fast? If you want it to steer slower... then... steer it slower.
Maybe I haven't really experienced the speed of a true high torque servo. I suppose I should try one out first.

I just didn't like how touchy the Holmes was when controlled by the Traxxas TX. A very powerful servo (I've yet to any issue with any HH parts) combined with a fast TRX4 and the not super precise TX, it was a little too easy to lose control of it.

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I’ve run a couple at 6-7.4v just to slow them down. All have multiple ratings for speed/torque at different voltage.

Or find a servo who’s speed is what you want


Hang up and Drive
 
While I don’t think there could be such a thing as a steering servo being too fast for me, there are several radios that allow servo speed to be adjusted as well as programmable servos from Hitec, Reefs, and other that would allow you to tune speed.
 
I've never paid close enough attention to the speed rating on any of my servos to have a point a reference for how fast, or slow, .13 sec/60° is.

But it looks like if I want to adjust the transit speed my best bet is getting a higher quality TX. I've considered buying one anyway and connecting all my trucks to it, just for simplicity. Could I keep them bound to the Traxxas TX at the same so I can share my trucks?

I appreciate everyone's input.

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You can use a shorter arm and increase the trim.

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I had a pretty good curve on the HH when it was in my TRX4 but I didn't even think about using a shorter arm.

I'm no servo biologist, would the servo be able to apply it's torque more easily (less load/stress) with the end of the horn closer to the point of rotation, at the cost of maximum steering angle? That would be fine if that's the case, I'm planning to limit the angle a bit anyway.

As mentioned, I'll have to wait for the servo to arrive to experience the transit speed of a true "high torque" servo. I might be happy with it straight out of the box.

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Shorter arm makes more torque but the arc of the arm makes the speed change away from center. I never have issues though.

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Shorter arm makes more torque but the arc of the arm makes the speed change away from center. I never have issues though.

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Okay. I thought I had that right in my head.

Thank you.

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Some short servo arms can cause issues with the back locknut hitting the servo body. Just clearance issues. Use locktite instead.

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Some short servo arms can cause issues with the back locknut hitting the servo body. Just clearance issues. Use locktite instead.

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I prefer to use locktite rather than a nut anyway.

The other potential issue I see with a short horn is the fact that it'd be going into a TRX6. From what I've read, and in my limited experience, the TRX can be a little tricky to find a horn that fits and clears everything correctly.

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I am not a Savox fan but I have had good luck with their 1230, strong but not as fast. It is a 6 volt but it needs amps. Unless you are running a ESC with a good internal BEC you will still need an external BEC for it to have all of its amperage power.
 
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The cheap metal horn Traxxas includes in the sport kit, and maybe others now, has the correct length and offset for the vast majority of 25 spline servos.

Many brand servos all have a different "deck height", meaning the distance from the mounting ears to the output shaft. Sometimes this requires shimming the servo up/down to keep the servo horn height correct to minimize bumpsteer and mechanical interference.

My Spectrum rugid allows you to slow down servo speed, but I only use it at 50% or so for dig, locker, and two-speed shift servos, seems to minimize strain and gear clash.
 
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I am not a Savox fan but I have had good luck with their 1230, strong but not as fast. It is a 6 volt but it needs amps. Unless you are running a ESC with a good internal BEC you will still need an external BEC for it to have all of its amperage power.
I'm currently running a HH brushless ESC (don't recall the model name/number of the top of my head), it's internal BEC is set low for the shift and diff servos and the receiver. As well and an external CC 20amp external BEC set at 7.4, with a splitter, exclusively for managing power to the servo.


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I'm currently running a HH brushless ESC (don't recall the model name/number of the top of my head), it's internal BEC is set low for the shift and diff servos and the receiver. As well and an external CC 20amp external BEC set at 7.4, with a splitter, exclusively for managing power to the servo.


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The 1230 is a 6 volt but likes lots of amps, not a good option for your setup. I have had a few 1212s. They are 7.4 and claim to be fast but they suck and get worse over time. Get one of those and be patient. It won't take long for it to slow down. Then it will get stiff and real slow and then it just won't work.

Do you have a remote that you can turn the power down on?
 
The 1230 is a 6 volt but likes lots of amps, not a good option for your setup. I have had a few 1212s. They are 7.4 and claim to be fast but they suck and get worse over time. Get one of those and be patient. It won't take long for it to slow down. Then it will get stiff and real slow and then it just won't work.

Do you have a remote that you can turn the power down on?
I have the patience to wait for a servo to slow down, don't have the patience to replace a servo that'll keep dying.

I'm currently using the original TQi TX that came with it. I can adjust the expo but I don't think I change overall power.

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I have the patience to wait for a servo to slow down, don't have the patience to replace a servo that'll keep dying.

I'm currently using the original TQi TX that came with it. I can adjust the expo but I don't think I change overall power.

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I have the Spektrum DX5 and one of my RCs has 4ws steer. I have direct power on 4s and the rear was to fast so i was able to slow it down. With a good receiver and controller you can do that, it may take 10-20 seconds to change it.
 
I have the Spektrum DX5 and one of my RCs has 4ws steer. I have direct power on 4s and the rear was to fast so i was able to slow it down. With a good receiver and controller you can do that, it may take 10-20 seconds to change it.
I've considered getting the rugged, or the FlySky GT5 (or whatever it's called) Something moderately priced that I can bind everything to.

Secondary question, If I got something like a DX5 and bound all my vehicles to it so I could grab the one radio and whichever vehicle I feel like driving, would they stay bound to the Traxxas TXs as well so I (and friends/family) could also drive more than one at a time? Or would I need to keep rebinding to whichever TX I/they are using?

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