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Old 03-05-2013, 01:32 AM   #1
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Default Help with motor choice

Ok so I am doing a custom build with a SCX10 Honcho, Im running the stock axles but I have a Tamiya 3 speed in it and its running a 10 tooth pinion and 2S. So I have tried a 13 turn brushless that i just had laying around cause I was excited to see it running which as I expected was rediculously fast and completely useless for slow 'scale' crawling.
So I looked around at some of the other motors that i have in my trucks and I tried a 32 turn brushless and it seemed to cog and didnt really have the torque that i wanted (wouldnt even make it up 1 step) but I think there is something wrong with that motor cause it seemed to cog in my girlfriends stock CR01. So then I tried a 17.5 turn brushless and it was getting more torque than the 32t and no troubles getting up the step but it still seems alot too fast.
So today just to give me an idea of torque, I rewound the mabuchi that came in the CR01 to a 46 turn and tried that out, It was alot slower like i expected, still not quite slow enough though, and it seemed to stall really easy on the step.
All of the testing on the steps were tried in first gear and when i put it in third gear to try to take off the 13t would eventually get up to speed very very slow acceleration, the 32t would cog and not move an inch, the 17.5t would cog for a little bit and then take off very slowly and the modded 46t was similar to the 13t.
All of this testing seems to be a bit weird to me as I was under the impression that more turns = more torque, which should mean that the 32t and the modded 46t should have performed better than the 13t and the 17.5t in high gear?

So getting to the question that I had in the first place, when i was starting to build this truck I was originally going to go with the tekin 55 turn but now im worried that it may not even be enough and I may have to look at something more like a 70t - 80t

Ultimately what I want is something that will give me somewhere around 4 - 5km/h top speed in low gear and still be able to accelerate pretty quick in high gear.
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Old 03-05-2013, 01:39 AM   #2
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Default Re: Help with motor choice

Anything over a 55 turn is completely unnecessary. You can't compare brushless power (torque) to brushed motor torque. If you want the power of a brushless system, get the 21.5t Novak motor. If you insist on using a high turn brushed motor get a Holmes hobbies Torque Master or Crawl Master.
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Old 03-05-2013, 01:45 AM   #3
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Default Re: Help with motor choice

Oh I forgot to say in all of that information, I wanted to run brushed because it will be going through water and from the very little research that I have done sensored motors dont like water. I had the 13t sensorless brushless in there with a summit tranny before and even with that when the motor was submerged it would cut out
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Old 03-05-2013, 01:50 AM   #4
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Default Re: Help with motor choice

Sensor or sensorless doesn't matter, they just don't like water. But then again I wouldn't suggest dunking a brushed motor either. It will greatly shorten the life of the motor. But if you are going to be doing so I'd buy dang near the cheapest motors I could find and have a spare or 2 on the shelf if you don't want to have the down time while waiting for another one in the mail.
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Old 03-05-2013, 01:58 AM   #5
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Default Re: Help with motor choice

sorry hate to contradict when im asking for help but brushed motors are usually 'run in' in water, atleast for racing use, it helps the brushes seat without wearing too much. I ran my stock 27t axial motor in water and mud almost every time I took it out trailing until i decided to upgrade the tranny. And i still have that motor, except I ran it on 24v just to see how long it lasted and it threw the plastic fan thing off the back and killed the comm
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Old 03-05-2013, 06:23 AM   #6
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Default Re: Help with motor choice

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sorry hate to contradict when im asking for help but brushed motors are usually 'run in' in water, at least for racing use, it helps the brushes seat without wearing too much. I ran my stock 27t axial motor in water and mud almost every time I took it out trailing until i decided to upgrade the tranny. And i still have that motor, except I ran it on 24v just to see how long it lasted and it threw the plastic fan thing off the back and killed the comm
People USED to use the "water break-in" method. Brush technology has progressed, motors are a bit better.
The 2 biggest crawler motor builders state to NOT do water break-in's anymore.

You can run in water, but, as stated, the brush life will be shortened.
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Old 03-05-2013, 09:07 AM   #7
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Default Re: Help with motor choice

Water break in has not been used in competition RC in over a decade easily, with the exception of the Sealed Silver Can motors and even they don't use it anymore.....I won over 30 National Titles in Racing, and not a single motor was ever broken in with water.

Surviving in water has a lot to do with brush choice, spring tension.......and the steps you take to care for the motor before, during and after the water.

Later EddieO
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Old 03-05-2013, 12:26 PM   #8
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Default Re: Help with motor choice

ok that being said can we get back onto topic? will a 55t motor give me the slow speed that im looking for in first gear but still be able to accelerate quickly in third gear? or should i be looking higher. i did briefly try the 32t with an 8t pinion instead of the 10 but it didnt seem to help that motor at all, plus i would prefer not to use the 8t because it would mean i have to shave a bit off my new motor case so that it fits.
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Old 03-05-2013, 09:20 PM   #9
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Default Re: Help with motor choice

I would throw a 27t turn into a honcho with three speed. Since you get into water, a cheap motor is best because everything will wear out fast. My TrailMaster sport would be a good match. RC4WD and Axial have some sealed can motors as well. A 55t sealed can on 4s wouldn't be so bad.
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Old 03-05-2013, 11:16 PM   #10
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Default Re: Help with motor choice

27t will be too fast I want max 4 - 5km/h in low gear and with the mabuchi motor that i rewound to 46t it still was going something like 10km/h
I would prefer to stick with 2S as I already have 5 2S batteries and dont really want to be buying more at the moment.
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Old 03-06-2013, 02:09 AM   #11
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Default Re: Help with motor choice

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Originally Posted by pbrgdmkj View Post
you insist on using a high turn brushed motor get a Holmes hobbies Torque Master or Crawl Master.
yeah thanks for that... you may as well have copied and pasted one of the previous posts.

Ok so I should have been more clear with the question, Im not asking for people to tell me that my motor will wear quicker than usual if im running in water as brushes and bearings are in most cases replaceable and cheapish, I also didnt ask for people suggesting that I use a brushless motor for running underwater cause it simply wont work, I am plainly and simply stating that I want to be able to get 4 - 5 km/h in low gear and be able to get a quick acceleration out of high gear. As previously stated I have tried and tested several motors that I had laying around before I go out and spend a few hundred on a new motor and esc but my experimentation didnt seem to give me a clear answer. I want to know whether a 55t motor on 2S will achieve what I want or do I need to get something with more turns? I dont really want to run 4s because firstly it means I need to either buy new batteries or find a place for a second 2S on my truck and secondly I understand that obviously more voltage = faster and I dont really want fast.
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Old 03-06-2013, 03:08 AM   #12
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Default Re: Help with motor choice

Then don't pull the throttle trigger to full throttle. And trust me, if you're going to be crawling the quick speed burst is nice you have when you need to hit it real quick to back or push through a roll over or to get you over that hump you're stuck on. A super slow rig is useless for anything but putting around the yard. We've all been there and tried the combo of slow vs fast and believe it or not, you'll find yourself using it more than you think.
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Old 03-06-2013, 03:14 AM   #13
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Default Re: Help with motor choice

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Then don't pull the throttle trigger to full throttle. And trust me, if you're going to be crawling the quick speed burst is nice you have when you need to hit it real quick to back or push through a roll over or to get you over that hump you're stuck on. A super slow rig is useless for anything but putting around the yard. We've all been there and tried the combo of slow vs fast and believe it or not, you'll find yourself using it more than you think.
Not helpful but Ill answer anyway, if I wish to go quick I will have 2 other gears for that? Its not really for crawling so much as trailing, I have a LCC for the rocks and yes I understand that having a bit of wheelspeed is helpful like I said 2 extra gears
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Old 03-06-2013, 03:21 AM   #14
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Default Re: Help with motor choice

Good luck shifting and reversing at the same time to save the roll over . People have tried to help and given you some good info. Sounds to me like your mind was made up on a motor before you even started this thread. Oh and in your first paragraph it says "slow scale crawling"

And depending on what ESC you have you can set the max power forward and reverse to limit your speed to what you want.
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Old 03-06-2013, 03:49 AM   #15
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Default Re: Help with motor choice

should have also mentioned that this isnt for comp use... its more for fun, so to me a roll over just means that i have to walk to flip it over and where the shift switch is on my controller it wouldnt be that hard to do anyway with a little practice.
"slow 'scale' crawling" well yes I did mention that however I would like to point out that I in no way said that that is what I wanted from the truck, All I said was that I tested the setup with a 13 turn brushless and it was rediculously fast and completely useless for slow 'scale' crawling.
You say that I have been given good info, this is true, but the information I was given was that water makes things wear quicker, it never really answered the question else I would have bought a motor already and it would be on its way to me.
Which brings me to my final point, my mind was almost made up on a motor before I started the thread, but that was before the testing, I have tried the few motors that I mentioned and none of them seemed to have enough torque to accelerate the way I want it to in 3rd gear so to me that would mean that I need more torque, and hence why I keep coming back to the 55t motor, Im not set on it but I know I need more torque.
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Old 03-06-2013, 03:52 AM   #16
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Default Re: Help with motor choice

Then get a quality motor instead of a crappy one. A quality hand wound motor will have gobs more torque than a piece of junk machine wound motor.
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Old 03-06-2013, 04:00 AM   #17
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Default Re: Help with motor choice

Ok now it seems like we are getting somewhere, but still not what I am after, I tried the makeshift 46t and before you or someone else says it I know its nothing compared to a properly constructed motor with regards to torque but it still wasnt enough to get it moving how I want it to, so thats what makes me say a 55t but what is the torque jump from a 45t to a 55t of the same motor? is it a bit? is it alot? because if its only a little bit then I can almost assume that I will need something bigger than a 55t.
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Old 03-06-2013, 04:03 AM   #18
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Default Re: Help with motor choice

Also what is the harm in getting something that may be a little too slow and then jumping up the pinion teeth? I have room to increase by probably 10 teeth with some modification but almost no room to decrease.
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Old 03-06-2013, 04:05 AM   #19
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Default Re: Help with motor choice

I had a 27t HH Torque master and it had tons more torque than any machine wound 55t I've ever owned. Higher turns doesn't always mean more torque when going between different brand motors.
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Old 03-06-2013, 04:06 AM   #20
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Also what is the harm in getting something that may be a little too slow and then jumping up the pinion teeth? I have room to increase by probably 10 teeth with some modification but almost no room to decrease.
Gearing it to high will also cause the motor to fail. To high of gearing will get the motor hot and burn it up.
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