Brushless motors in the lego world - general topic

[gyenesvi]

12 hours ago, vergogneless said:

First, I’ve been experimenting with a new way to mount the gear onto the motor shaft. I replaced the gear’s cross pin with a hole matching the motor shaft diameter (3.17 mm for the A2212). You have to press it in with a hammer, and once it’s in place, it won’t move a bit. I think this is the most reliable solution so far, and it also saves some space.

If the printed gear holds up well, that looks like a really nice compact solution, I like it!

12 hours ago, vergogneless said:

For the first time, I’m also using a servo other than the Geek Servo: the MG90S. Once adapted to the LEGO system, it’s even smaller than the smallest Geek Servo, yet it offers a torque of 2 kg compared to 0.5 kg is a bit faster and more precise, and all of its gears are metal.

Interesting, and what did you need to do to adapt it to the lego system? Are you using a servo horn based or a gear based solution?

[vergogneless]

3 hours ago, gyenesvi said:

If the printed gear holds up well, that looks like a really nice compact solution, I like it!

I’ve tested all the existing solutions, and this one is definitely the simplest, strongest, and most durable. Since the diameter perfectly matches the motor shaft, you really have to hit it hard to insert it, which creates an extremely tight fit. The alignment is also absolutely perfect! To give you an idea, I can’t pull it off by hand, and even with pliers, it’s a real struggle. You actually have to split it open to remove it more easily.

Interesting, and what did you need to do to adapt it to the lego system? Are you using a servo horn based or a gear based solution?

You have several options, I based mine on this one (for the dimensions):

https://www.thingiverse.com/thing:4496227

Because I needed something more specific for my build.

Otherwise, there are also generic versions available: https://makerworld.com/fr/models/1778626-9g-servo-lego-technic-compatible-shell#profileId-1894418

To transfer the steering, I also designed a custom 3.5L horn. But for something more generic, you can use this one:

https://makerworld.com/fr/models/1781412-9g-servo-lego-adapter#profileId-1897609

Or that one, for example:

https://www.thingiverse.com/thing:6010292

 

[gyenesvi]

1 hour ago, vergogneless said:

To transfer the steering, I also designed a custom 3.5L horn. But for something more generic, you can use this one:

Those adapters actually look quite good, simple and easy to print! This could be really useful solution to make servos in alternative form factors (for example flat to put on a straight axle).

[vergogneless]

I also found a mount for a different setup, created by @HorcikDesigns, for the SG90, but I’m not sure if it also works with the SG90S!

https://makerworld.com/fr/models/165631-servo-sg90-to-technic-adaptor-for-brick-models?from=search#profileId-181863

[keepbricking]

Hey everyone!

I have made my IWD lego car, the motors are up and running,  it looks a bit bad, but that's okay

I don't know how to share the video, bricksafe is not letting me create an account nor flickr

@janssnetturns out that I didn't need to setup ESC for DShot, since it takes various signals 

The flight controller only sends the type of signal chosen, the ESC takes and automatically translates any signal it supports 

Yes I needed to share ground between RX and ESC, but that was done simply through a 5v BEC

Now I only need to wait for the 3d-printed tyres to get this car on the road 

I have a feeling it could do 90+km/h! but I do not have a speedometer

[Aurorasaurus]

6 hours ago, keepbricking said:

Now I only need to wait for the 3d-printed tyres to get this car on the road 

What material are you using? I'm pretty sure you'll encounter traction issues if you're using high hardness tpu, and printing issues with low hardness... but I'd love to see a solution, good luck!

[keepbricking]

@AurorasaurusI just asked for PLA 

why would I encounter traction issues when the lego rims work fine?

besides I'm gluing the tyres to the rims

[Aurorasaurus]

17 hours ago, keepbricking said:

@AurorasaurusI just asked for PLA 

why would I encounter traction issues when the lego rims work fine?

besides I'm gluing the tyres to the rims

I just assumed that when you said "3d-printed tyres" you meant, well, tyres... not rims. But I understand now :)

[keepbricking]

OK, sorry my bad

But I will also print some off-road tyres, TPE is also an option, it is what Lego tyres are made out of

but TPU is also okay, just shiny, which hardness and brand would you recommend?

[Aurorasaurus]

On 11/11/2025 at 11:16 PM, keepbricking said:

OK, sorry my bad

But I will also print some off-road tyres, TPE is also an option, it is what Lego tyres are made out of

but TPU is also okay, just shiny, which hardness and brand would you recommend?

No worries ;)

TPU from my experience with it, admittedly only 95a, is far too rigid for tires. I've used esun brand filament because it's cheap where I am.

[2GodBDGlory]

I've tried printing TPU tires, and while they were soft enough, they weren't grippy at all. You could flex them, but they wouldn't stick

[Asakbar78]

On 9/7/2025 at 3:46 AM, gyenesvi said:

Version 2 of my motor housing! :)

As I started to build, I realized that it would be good if the sideways mounting holes would be vertically in the middle of the motor, because then it would be possible to hold it between two beams that are just the right height for dropping the output shaft right under the motor with one gear mesh; the simplest ever driveshaft (see below). So I designed another housing, where I could add pinholes in a row, and even round off the whole thing, and change the assembly so that it requires less screws, holding the back panel from the side. I also removed the back cover to prevent the motor from overheating. This version looks like this, as slim as it could get:

The first pinholes (towards the face) are full stud deep, while the rear ones are only inverse studs for half pins.

The new mounting points hold the whole 3L front section firmly, so there is no need for stabilization on the back. At the same time, it can be assembled using only the screws that come with the motor, and it is easy to disassemble and assemble again multiple times (the wear of the screw holes does not matter, because it is actually the head of the screw that holds the back wall). Another advantage is that now the wire can come out in a diagonal, allowing the motor to be tilted 90 degrees and mounted from the front without the wire interfering with the beam that runs next to it. The motor can also be mounted so that the wire comes out on the top, if needed.

This is how it looks in more detail:

Of course, it is possible to combine the two designs, and make a square version that has more mounting holes than the first version had:

Now as for building, this is how the most compact 4WD off-roader driveshaft for live axles could look like (two gear ratios are possible):

I have built this into a small scale 4x4 chassis and the performance is just great, super smooth control, great top speed! I guess I'll just open a new WIP topic for showcasing it!

 

Would you be willing to share the file for this design?

[gyenesvi]

6 hours ago, Asakbar78 said:

Would you be willing to share the file for this design?

Here is the link to download for the round one.

[keepbricking]

How do I share the video?

It is up and running and VERY FAST

[Zerobricks]

1 hour ago, keepbricking said:

How do I share the video?

It is up and running and VERY FAST

Upload it on YouTube and paste the link. 

[keepbricking]

@Zerobricks! never thought I'd see you on a brushless forum, since you're well, the head of development of Buwizz team

The car broke 

I'm currently building a new car with an actual RC car motor since that had no reverse and bad control

maybe Buwizz can also try experimenting with brushless somehow, but I don't know

maybe you want to stay true to Lego compatibility, or you can somehow make a hybrid 

you can control Lego brushed motors with inbuilt ESCs and use PF and PU both and utilize the rotation sensors

on the other hand you could also attach a brushless motor and ESC for better power to weight ratio and SPEED!!!!

I know it's a dumb idea, just popped in my head, I just wanted to inform about the car

 

 

[ejayb]

Excuse me, this is not directly related to brushless motors, but I believe the experience here might help.

As a train builder, I'm a fan of LEGO's 88008 motor. Not only for it's compact size, but also for it's slow speed ability due to PID control and the use of PyBricks with PUP.

Unfortunately I've had two of these motors fail and they are now discontinued, the price will only rise. 

I have sourced what I believe to a replacement motor and I will try to remove the gear from the original with heat, set it onto the replacement and shorten the shafts. 

 

Alternatively, has anyone experimented with reusing the 88008 control board with a completely different motor and housing?

 

[janssnet]

Recently finished an updated version of my "ONE_PIECE_3D_PRINTED_LEGO_BOAT"  

Moved away from the LEGO drivetrain, wasn't waterproof. Converted to non-lego parts for the internal mechanics (servo, driveshaft, motor-mount). 

Result is pretty good. Please have a look at the video here.

https://drive.google.com/file/d/1G1vxLrbVExNiBES1nfUgEu7qyVhFcGDE/view?usp=sharing

What i'm most thrilled about though is the updated version of Nano Banana (AI image editing). If you want your LEGO model to come alive, give it a try!

 

[Krxlion]

I think that the pilot said, "No, thank you, I'm good.". And decided not to join live journey on this boat. :D Great stuff, not a typical Technic thing, but I believe it is enjoyable to watch your work flowing on the water with ease.

One thing though, after your phenomenal work with the in-wheel-motor car, are you planning on going back to land vehicles with new ideas?

[janssnet]

 

Quote

are you planning on going back to land vehicles with new ideas?

 

Yep! The in-wheel-project is not finished yet. Working on a (if possible) faster on-road rc car right now and waiting for a third party's response to get a GO on a next LEGO project ......

[keepbricking]

Got my A1 Mini!!!!!!!!!

It truly is an excellent machine, I'm currently doing calibration testes to ensure maximum quality

I think maybe I could print R156 bearings, I know how to and have designed them, but Bambu studio shows that the walls are too thin and when I lower the line width, it barely or doesn't extrude

Does anyone know a potential solution for this problem ? I would be very thankful, I can assemble a bearing with 1mm balls 

Finally I could have proper fitting bearings for lego, I'm not so privileged to aliexpress like you European individuals

I can have unlimited possibilities to expand my lego creations, I'm very thankful for the printer

I even know 3d modelling now