Jump to content
Tamiya_Cars_4_Life

Does anyone know what size pinion I should use for a GoolRC 3650 3900KV Brushless Motor?

Recommended Posts

I am about to purchase a GoolRC 3650 3900KV Brushless Motor for my Tamiya Racing Fighter. I need to know which sized pinion gear to use since I am switching from brushed to brushless mode. Nowhere have I seen how many turns the motor has or which sized pinion gear to use. 

 

Cheers,

Max :)

Share this post


Link to post
Share on other sites

I'd use the kit one, brushless motors produce much more torque. No need to go for lower tooth count.

Run it and you may even find if the motor doesn't get too hot, you can run a larger pinion.

  • Like 1

Share this post


Link to post
Share on other sites

Thanks Bromley! Just to be clear, I should use the one that switched from my Torque Tuned to Sport Tuned and then my GoolRC? How would I know if it gets too hot? I have an ESC with a fan. So, if the motor doesn't get to hot, what would be an example of a larger pinion gear. What would be the effects from a larger pinion gear?

Sorry for pestering you!

 

Cheers,

Max :)

Share this post


Link to post
Share on other sites

If you can touch the motor for 5-6 seconds. Without discomfort your motor temps are fine.

It may be worth investing in a steel pinion ultimately to insure it lasts , but to start with just run the stock kit pinion.

If the performance is suitable and motor is not overheating your good to go.

Stock pinion size is 17 tooth I believe, if your happy with the motor temp try going up to a 19 tooth. Without mods this is the largest pinion you can fit in a DT03. 

  • Like 1
  • Thanks 1

Share this post


Link to post
Share on other sites

Yeah I’d do that :)

I think in my neo scorcher I did change but I did that before I went brushless just coz

i have a cheapo cooling fin on my goolRC motor and a little air bent on the shell 

TLJKzec.jpg

 

im running it with a 3s lipo 

wow it’s fast

 

i have the red goolRC one in my racing fighter 

XNqpY2V.jpg

qAkSGKN.jpg

but I’ve never run it :)

 

JJ

 

  • Like 1

Share this post


Link to post
Share on other sites

In general terms...

Smaller the pinion, more acceleration. 

Larger pinion, higher speed.

This isn't the whole story. The way you drive, where you drive and motor choice can alter pinion choice but for general running you should be fine with that setup on 2s lipo.

  • Thanks 1

Share this post


Link to post
Share on other sites

It’s just a cooling fin but you won’t be able to fit it on your racing fighter because it’s enclosed 

if it’s getting too hot I’d be inclined to maybe modify the housing the motor sits in to get some airflow 

But yeah it’s my neo scorcher 

hhKT536.jpg

it goes so fast it sheds tyres - mainly from going sideways trying to slow it haha

JJ

  • Haha 1

Share this post


Link to post
Share on other sites

With the motors and pinions it’s like gears on a bike and your legs 

big gear and your legs start to burn because of the load needed to turn the wheels - but you have fast top speed

small gear and you accelerate fast and your legs don’t burn too much yet your top speed is limited 

JJ

  • Thanks 1

Share this post


Link to post
Share on other sites

Tbh you might find the brushless too much for the racing fighter 2wd and motor out the back

good thing with the goolRC is that they are a bargain and perform so well

JJ

  • Thanks 1

Share this post


Link to post
Share on other sites
1 minute ago, Problemchild said:

With the motors and pinions it’s like gears on a bike and your legs 

big gear and your legs start to burn because of the load needed to turn the wheels - but you have fast top speed

small gear and you accelerate fast and your legs don’t burn too much yet your top speed is limited 

JJ

I never thought of that! Thanks! Now it'll be easy to remember!

Share this post


Link to post
Share on other sites

Yeah it’s all about the load on the motor (well that’s how I try and think of it anyway)

JJ

Share this post


Link to post
Share on other sites

Just checking - did you order the combo with the motor and ESC?  Or are you planning to run the TBLE-02S?  The TBLE-02S won't run that motor as it only runs sensored brushless motors, and that motor is sensorless.

Also, consider buying something like this

https://www.banggood.com/GS320-Laser-Digital-LCD-IR-Infrared-Thermometer-Auto-Temperature-Meter-Gun-Non-Contact-Sensor-p-1112064.html?rmmds=buy&cur_warehouse=CN

You can easily check the temperature of your motor, and a $20 temp gun can save many $180 motor's over its life.  

As an aside, just looking at temp guns, they are about twice the price than when I bought mine and many are sold out.  Covid19 I guess, I've seen these in so many news clips being used to check people's temperatures before allowing them in places.

Share this post


Link to post
Share on other sites
2 hours ago, Tamiya_Cars_4_Life said:

@Problemchild, what do you mean "the motor out the back?" 

 

Thanks!

Doesn’t the racing fighter have the motor hanging out the back of the car?

that takes the weight off the front wheels and with a brushless when you accelerate it’s gonna try and wheelie ;)

do you have the orange or the red combo?

Either are fine 

 

JJ

Share this post


Link to post
Share on other sites
1 hour ago, Jonathon Gillham said:

Just checking - did you order the combo with the motor and ESC?  Or are you planning to run the TBLE-02S?  The TBLE-02S won't run that motor as it only runs sensored brushless motors, and that motor is sensorless.

I got the combo, here is the link. https://www.walmart.com/ip/GoolRC-Upgrade-Waterproof-3650-3900KV-Brushless-Motor-with-60A-ESC-Combo-Set-for-1-10-RC-Car-Truck/103963554?wmlspartner=wlpa&selectedSellerId=101001360&adid=22222222227318745358&wl0=&wl1=g&wl2=c&wl3=397711911576&wl4=aud-430887228898:pla-839281527990&wl5=9007202&wl6=&wl7=&wl8=&wl9=pla&wl10=128133340&wl11=online&wl12=103963554&veh=sem&gclid=Cj0KCQjwybD0BRDyARIsACyS8mt1T374USDzXUI2Pe_NtJ-Gv0Gmc7H2oUD0n6ORFLyI66TzUyUVyTMaAtbhEALw_wcB

What do you mean by "are you planning to run the TBLE-02S?  The TBLE-02S won't run that motor as it only runs sensored brushless motors, and that motor is sensorless." Does that mean the ESC won't run with the motor because I got the combo.

Sorry, I'm just pretty baffled here!

 

Thanks,

Max

Share this post


Link to post
Share on other sites
5 minutes ago, Problemchild said:

Doesn’t the racing fighter have the motor hanging out the back of the car?

that takes the weight off the front wheels and with a brushless when you accelerate it’s gonna try and wheelie ;)

do you have the orange or the red combo?

Either are fine 

Yes, the motor is hanging out the back of the car in the rear gearbox. And yes, I have the orange GoolRC combo. It is a 3900kV motor.

Share this post


Link to post
Share on other sites
23 minutes ago, Tamiya_Cars_4_Life said:

I got the combo, here is the link. https://www.walmart.com/ip/GoolRC-Upgrade-Waterproof-3650-3900KV-Brushless-Motor-with-60A-ESC-Combo-Set-for-1-10-RC-Car-Truck/103963554?wmlspartner=wlpa&selectedSellerId=101001360&adid=22222222227318745358&wl0=&wl1=g&wl2=c&wl3=397711911576&wl4=aud-430887228898:pla-839281527990&wl5=9007202&wl6=&wl7=&wl8=&wl9=pla&wl10=128133340&wl11=online&wl12=103963554&veh=sem&gclid=Cj0KCQjwybD0BRDyARIsACyS8mt1T374USDzXUI2Pe_NtJ-Gv0Gmc7H2oUD0n6ORFLyI66TzUyUVyTMaAtbhEALw_wcB

What do you mean by "are you planning to run the TBLE-02S?  The TBLE-02S won't run that motor as it only runs sensored brushless motors, and that motor is sensorless." Does that mean the ESC won't run with the motor because I got the combo.

Sorry, I'm just pretty baffled here!

 

Thanks,

Max

Yep nothing to worry about.  I was just asking in case you had bought the motor on its own and not the combo.  You'll just replace the current brushed motor and TBLE-02S ESC with the new combo.  At the risk of confusing things more, you can buy a sensored brushless motor on its own and use the ESC that the kit came with and not buy a new combo.

  • Thanks 1

Share this post


Link to post
Share on other sites

A sensored ESC takes readings from hall sensors built into the motor, which tell it where the rotor is at any point in its rotation. This means that it can always power up the correct stator coil, giving a smooth throttle response even from standstill.

A sensorless ESC lacks the ability to take these readings, so has to "guess" where the rotor is until it is spinning fast enough to generate back EMF. This can give rough and jerky throttle response at low speeds, known as "cogging".

"So why aren't all motor/ESC combos sensored?" you may ask. Well, while sensored setups are smoother and generally quicker off the line, and are thus the typical choice for racing purposes, the added complexity tends to make them more expensive and seldom waterproof. You can typically get a more powerful (but less refined) sensorless setup for less money, making them popular wish bashers.

  • Thanks 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...