Water and dust proofing a mountain boards motors

I’m building a mountain board with 2 SK3 motors. Since they are open motors and require airflow for cooling, I need to protect them from the elements while still getting good cooling. I think i have a good idea about how to do it. But i would really like to see what you guys and gals are doing to protect them

Sorry im not able to link it, but I remember a vendor around here selling some sort of mesh screen that fits 63xx motors… that one goes inside the can.

This one: https://pwrboards.com/collections/black-friday-deals/products/pwr-motor-case belongs on the outside


Cool. I’ve never seen those before.

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I think sharing your idea of how to protect them would be smart. People can then comment on wether its a good idea or not. :wink:

Anyway, protection againts water isnt necessary, only the bearings can take damage (and sensors if you have them, sk3 doesnt). These can be replaced by ceramic ones, but I have never had problems with rusting motor bearings.

Protecting against stones is usually done by inserting some sort of mesh where the motor is exposed.

If you want to protect against very fine debris you’ll need to seal the motor completely. This will trap alot of heat inside the motor and is usually not recommended, as these motors get super hot (at least if you draw alot of power) even with airflow. They will get even hotter if sealed 100%.

Trampa offer the mesh with the frame for their motors they use

Something like this should be expanded upon. Its a shame the size of our trucks often means paper thin levels of seperations between motors… no room for them to fit :frowning:

Sure. I’ll whip up a rough 3D drawing. My hand drawings are not very usefull :smile:

I was researching the same not too long ago, here is the post:

The one @anon64938381 mentioned looks really nice too and seems to offer more protection as well. but sk3 motors are longer than 74mm, I don’t know if it actually gonna fit.

Here is a rough sketch of what i have in mind. 1 motor per end driving 2 wheels and then covering with this. The sketch obviously needs the fine mesh for the 2 vents and the mount holding the motor needs large ventilation holes.

Perhaps also add an 80mm fan blade for better airflow than the motor can provide


Thanks! I don’t know why i didn’t find that thread in my search

Are you going to replace the standard sk3 shaft, with a longer 8mm rod?

No. I’ll just be using a rigid coupling for the 8mm shaft. No need to tear the motor apart. It will of course be keyed, so it won’t slip.

How are you going to connect the coupler to the motor?

On one end I’m going to use the original shaft and on the other end I’m going to use the accessory that comes with the motor that adds a 10mm shaft on the backside

You could use a medium mesh strainer, cut it and shape it properly, just cover the motor to protect the magnets to get metal debris during the process. For a mountainboard you will need torque, I hope your motors a very low Kv rated (75 or less), and a ver high battery C discharge rate (60 or more). Motors need to be ventilated , I would not cover them, and I do not think you need to protect them from water (only the sensor and the wires maybe). Just my opinion…

everything else is under control. I would just like to see how people have protected their motors, to see if anyone have a better or cooler looking solution.

75kv motors? With standard gearing that translates to ~18km/h…

Mines has a 3D cover with a spiral looking fan. So while the motors are spinning, the spiral fan shape helps with air flow. Been riding through dirt and little rains with no problems. Literally just got home and rode through puddles ttoday


CCU “Here is a rough sketch of what i have in mind. 1 motor per end driving 2 wheels and then covering with this. The sketch obviously needs the fine mesh for the 2 vents and the mount holding the motor needs large ventilation holes.”

He needs a lot of torque to move this idea…better 18 km/h than not moving at all…I might be wrong…but big mountainboard wheels under this set up, I would go very low Kv…Chain, Gear drive, Belt…different story…

Our brushless outrunner can run in wet conditions as the phase wires are isolated by there own already. Problems you usually get from the sensors inside. Just open the can and cover the hall sensors and pcb with some of your girlfriends nail polish :sweat_smile: Or epoxy and you good to go.

If you worry about stones etc getting on your motor, I think @MannyM0E solution is pretty good looking and effective