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Alexei

ESC overheating, gearing problem?

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so, i have this TT-01 which is old and my first real RC car that got me into RC. it has a GM Racing Evo 4 brushed motor, i think it is 12x2 turns but im not sure. it doesnt run for more like 5 minutes, then it completely halts functioning. i have noticed the heat sinks on the ESC gets too hot to touch. after cooling down, it will run again just fine, until the ESC gets hot.

i have researched a little, and sounds like the gearing could cause this. i do have the stock gearing installed. but i know about nothing about gearings and need help. what gearing should i go for? i just want it to run so that it doesnt overheat. it is not a track car, just a street fun time RC car. 

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The ESC is going into thermal shutdown to protect the electronics. What ESC are you using? That's a relatively low turn motor and would require a pretty small pinion/big spur to not over heat.

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the ESC is a Nosram Patriot, instructions says for over 7 turns. i dont remember if i have the stock motor and ESC anymore, but will check.

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That ESC should be able to handle the 12 turn motor as long as the motor isn't being strained. To the best of my knowledge the standard tt-01 came with the gearing as low as possible, 19t pinion and 61t spur. At that rate there is not much you could change other than reducing the advanced timing on the motors end bell.
 

Also does the drivetrain seem to operate smoothly without the motor installed?

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the car is pretty dirty, and has never been cleaned off. i do plan do take it apart and totally clean it. but i dont think the drivetrain is much obstructed, on ther other hand the suspension arms is not moving freely. though i will take the motor out and check the drivetrain when my work space is clear.

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A good clean out might help by the sounds of it , axles and bearings might be gummed up and possibly grime in the motor / pinion , old grease in the gearbox

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just started the cleanup now. as i dissambled it, i checked friction on various parts. the drivetrain have hardly any friction, but stering on right side and the suspension arms have some considerable friction. front right side suspension arms just keeps its position when lifted, and doesnt fall down.

i will complete the cleanup and see where it takes me.

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Full tear down is in order. Clean her up and she'll be good as new. The hanging suspension is probably just some dirt in the hinges or ball joints. There is a lot of plastic on plastic connections in the TT-01 suspension so it is susceptible to binding.

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For gearing think about your push bike 

if the gearing is too high (big front and little at back) then your leg muscles (motor) will start to burn.

same for RC car

if the gear at the front (motor) Is too big and the one it meshes too is too small then the motor is going to struggle 

so small number of teeth on motor into large number of teeth is easiest for the motor :)

if you are running stock though, it’s potentially the ESC is feeling a bit old 

you could add a fan or make some cooling holes in the body work 

in the end though a $30 brushless combo from goolRC Could fix your issues :)

JJ

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the overheating problem is one i have had for as long as i remember, also from the moment the motor and ESC was new. i never got to do anything about it, and then this TT-01 has been packed away for 13 years since i had other things to focus on.

i wouldnt want to spend too much money on it, and prefer to keep the motor and ESC i already have. but if i can get a good motor + ESC combo for just 30$ AND not having this problem anymore, then that is something i would definitely consider.

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Alexei, are you running the smallest pinion and largest spur gear that can fit for the chassis?  12 turn motor has a lot more RPM, the gearing needs to be changed compare to stock motor.  

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image.png.e354baf8109e27e143dcffe44f0b6c8a.png

 

19T pinion, 61 spur, final ratio 8.53, mounting position A.  Even with that gearing, it is still over geared for 12T motor.

Mod motor 10 - 12 turn would be good with a 10:1 to 11:1 final ratio.

Like another person said, try move the timing to zero degree on the motor's end bell.  Even with that, I still think the gear ratio is over geared.

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gearing is just the stock that came with the kit. spur is 61T and pinion is 19T.

will look into the timing. its not something i have done before, but it will be a little while before i can get to do that. i have the TT-01 in pieces in a cleanup process and discovered some damaged parts i will replace.

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Here is a Tamiya's own graph of the silver can vs Sport Tuned.  

I6Qj1IV.jpg

The silver can tops out at 18,000 RPM (red line:  Silver can gets 1000g/cm, while Sport Tuned gets about 40% less).  Note that they are using constant power. (Probably not powered by battery, but some using massive factory power supply just for testing)  If you look at the orange like I drew, the silver can might be getting like 600g/cm torque, while Sport Tuned is getting like 400g/cm.  

This is a well known problem with brushed motors.  Faster motors produce less torque at given RPM.  Faster motors do have more torque in the end, but they simply do not produce more torque until the RPM gets way up there.  This is why the general rule of thumb has been "faster motor, lower gearing."  If you want to run a 12x2 motor, the pinion needs to be a lot smaller than the 19 tooth pinion.  But there is no such option available. 

I also have a 12t motor myself.  I couldn't install it anywhere because none of Tamiya cars I own have gear ratios low enough to utilize the full potential of the motor.  With Tamiya's gearing, the strongest Tamiya motor you can use are Super Stock 23t motors.  Probably the 4 most populare motors they sell are Sport Tuned, Super Stock BZ, TZ, RZ, all 23t motors.  I don't think Tamiya even sells a 21t motor, let alone 12t.  It's not that they don't want to make money, but lower turned motors would bring bad reputations to Tamiya, because their gearing just won't allow lower turn motors (Super Stock motors also require stronger ESCs than TBLE02S, probably due to more aggressive timing than Sport Tuned).

Fortunately, that does not mean that you have to give up speed.  You could go with a 10.5t brushless motor and an ESC that could handle it.  Brushless motors have greater torque than brushed, so even with a 19t pinion, it should do just fine.  

 

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so going with my 12x2 turn motor wasnt a good idea from the start. well, it was done back when i was 14 and just wanted fast car, so...

i dont want to put too much money into it because i dont use it that much. if im going to buy new motor/electronics, i would rather start out with a new chassis and just keep this one as a time capsule or something along that.

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Once it's had a freshen up, I'd nail a fan onto the ESC,  fans are cheap enough and work well (running 3 on a Dark Impact! 🙄

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Keeping the esc cool wont stop the motor overheating though.

Best to get that 12t out of that car in my opinion :(

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9 hours ago, graemevw said:

Keeping the esc cool wont stop the motor overheating though.

That's why I've 3 ! 🙄😂😂

 

2020-05-14_10-53-00

 

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I cut a few vent holes in my neo scorcher as well....

WCJwSgD.jpg

This help keep the motor cool (which has aluminium fins on

f7157Fw.jpg

JJ

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ok, the TT-01 has been totally cleaned up and drivetrain runs smoothly. i tried running it with the wheels not touching the ground, but the ESC would still warm up in a few minutes. it is possible that i wont get this fixed without changing motor and ESC to something else. not sure if a fan on the ESC is enough.

well, i have been having some interest in a new chassis, so if i decide to buy one, i will take this knowledge with me.

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