janssnet

Sorry bout that! You are absolutely right, inner diameter is 5mm.

Great method, works well, also under serious load. Adjustment ring with 3mm screw. Best dimensions: 5mm inner diameter, 8mm outer diameter. With a bit of luck the axle runs free between two LEGO motor mount links (might require some sanding of the ring to make it < 8mm). https://drive.google.com/file/d/1CFitfryYzmyNKNo-57e2chE14JZNydfd/view?usp=sharing

First thing that comes to mind is that the ESC is not 'armed' properly. Meaning that the ESC has not gone through the initialising process properly when being turned ON, and therefore doesn't know which PWM values are 'neutral'. Please have a look at the ESC's manual (if available) to learn about 'arming the ESC'. Sometimes these ESCs want to receive a max throttle signal at start.

Would be good to do a load test for this mount. Let's see if I can come up with something coming weeks. And yes agreed, when the load/weight increases, you would need a gear train, ideally with some planet gears to divide the torque properly. The motor is a very simple 1750kV outrunner. Mounting holes M3 - 16mm apart, of course :) Advantages of this motor: cheap, no cooling required (under normal conditions) and the motor shaft can be shifted, allowing you to mount the motor on the front or rear side. https://nl.aliexpress.com/item/4000121770043.html?spm=a2g0o.productlist.main.13.57bd7392rPapJu&algo_pvid=4f7ea6c9-bad3-4525-9324-cb00b53439e6&algo_exp_id=4f7ea6c9-bad3-4525-9324-cb00b53439e6-6&pdp_npi=4%40dis!EUR!3.89!3.89!!!4.09!!%402103847817019402965684078e398d!10000014597782070!sea!NL!173983871!&curPageLogUid=JhLCITsdifaM Regarding the connector trick ... well spotted ;) If you use 3.5mm bullet connectors and isolate them with heat shrink tubes, most of the time, you end up with a connector that fits the 4.8mm LEGO hole perfectly. Depends on the thickness of the tube.

Sure, you could use 18651 (3L axle pin), but you would (indeed) have to drill a round 3mm hole in it first. There is however no real need to fix it at the other end. In fact it would only increase drag. Please note, the motor shaft goes all the way through the motor and the 2L axle pin is strong enough to give serious torque. Have a look here ...

Hi folks, Thanks for keeping this thread alive. Great content. In case you're looking for a solid way to mount your LEGO gear to a brushless motor with a 3mm or 3.17mm shaft, have a look here. https://youtube.com/shorts/jh-xOvj5AE4

Great subject folks! In case you're looking for (more) inspiration how to mount BLDC motors to LEGO, please find a few additional suggestions hereunder. ‎LEGO BLDC.‎001 ‎LEGO BLDC.‎002 ‎LEGO BLDC.‎003 ‎LEGO BLDC.‎004

Thanks for initiative @Krxlion, love this subject! Great to read about your experiences and additions. Have been incorporating brushless into my LEGO project for years. Lots of fun. Please find the latest attached: RIB with brushless (drone) outboard motor Was thinking of doing a short video/slide deck: Top 5 mounting tips to run your LEGO project brushless. Useful you think? https://www.flickr.com/photos/153697698@N03/52809695671/in/dateposted/ https://www.flickr.com/photos/153697698@N03/52809132637/in/dateposted/

Just finalised a video presenting the iWD4 project. What a ride it has been! Let me hear your views, will this become a new class of RC Car racing?

It sure happened! Got me into the freezing cold water :(( Regarding the iWD4 car ..... it's ready for footage. Had to fix a boat first. Just needed a push to start recording it. Your post surely helps!

Great stuff Krxlion! My advice: do both! Fix the gyro-stability and (by all means) implement positive castor. The latter is a serious revision, but is very rewarding. A slight angle (like 8 degrees) can already make a huge difference in straight line stability.

Bit reluctant to post this, since this boat is made of a 3D printed hull, the RIBs are made of insulation tubes, the electronics are all RC parts and the motor is a brushless drone motor. NEVERTHELESS ..... It looks like a LEGO boat, don't you think?! And it works great! Happy to share more details if there is interest, happy to remove it, if it's too little LEGO for the forum.

Funny you should mention this ..... That is exactly how I started. Inspired by these guys https://mammuth.works I thought I could do my own LEGO-version of this. Please have a look at the first demo set up. 4 Brushless motors, magnetics & hall sensors on every wheel-hub and 2(!) Arduinos. First goals: 1. Sync motors to get perfect straight line stability 2. Implement a software-differential. The result: A horrible driving experience. Feedback loop is too slow to react on bumps in the road and motors (and ESCs) take too long to compensate for sudden moves. That is how I ended up doing an 'independent 2 wheel drive' car with a simple Arduino based sw-differential and a gyro. Have a look at the video here. The gyro is doing a far better job than trying to sync 4 motors. A sudden change in yaw, is immediately compensated by steering in the oppositie direction. The sw-diff is a simple mixer, reading the steering PWM and include this into the throttle PWM. Gives (adjustable) understeer or oversteer. Works nicely. The most important finding however, when using in-wheel brushless motors, there is no need for differentials! The motors easily adapt in the turns, offering great torque while cornering and the gyro keeps things perfectly straight (when the right ESCs are used). As Mammoth says, this could well be the next gen in RC racing. Nevertheless, doing a small scale torque vectoring project, to simulate the real world is still an interesting challenge. Have a look here https://hackaday.com/2014/07/12/independent-wheel-drive-rc-car/ Great project but haven't seen the car driving straight at full throttle. Let me hear your thoughts on this ....

Most drone motors (with these dimensions) have 4 M3 mounting holes. 2 with a 19mm distance, 2 with 16mm distance. The latter fits LEGO perfectly No drilling necessary.

Suspension is symmetric. However, the front wheels have positive castor angle of 8 degrees. To improve straight line stability. Is not an easy fix, but makes a huge difference at higher speed. Please find some extra pictures showing the in-wheel motors. These 5010 motors fit perfectly. Are relatively low cost and available at low KV's, which gives more than enough torque to drive a car.