Extreme Off-roader I 2 Motor 4WD I Custom gear drive I Mefo 11x4.5-5 I Ice Spikes I 1.7kW battery I Trampa I Focbox I 6384

Hey guys! Figured I would finally document one of my builds.

This is my 2nd complete build. I didnt really bother with doing a build thread of the first one, as it wasnt really anything unique, just a normal longboard build.

This one however is a bit more special :yum: The main goal of this build was to be able to tackle some nasty offoroad trails, and being able to do deep ish snow. There is a lot of snow in Norway at winter time :sweat_smile:

I guess I can start off with some cad photos: 20 56

As you probably can see, I got a lot of inspiration from @Duffman `s 4WD monster board :star_struck:

However this one is a bit different as I am going to use a 2 motor 4WD setup, at least to start with. If its too little power I might do 4 motors in the future.

As I am still waiting for a focbox replacement from enertion, the board is only 1 motor 2WD. It actually works quite well even in snow, however when the snow gets deeper, like 10cm, the power from only one focbox is way too little.

Photos from 2WD testing: IMG_0413 bbJgKOJXR02yCrg%20Xq%20ahQ YCIffmCcTFKfuBG9uEkuBw 0lvZ5%20e1QyWtUNIvNhtvIQ (In conditions like these the single focbox overheat with in a few seconds of full power :sweat_smile::laughing:).

As the board is far from finished I will update the thread once I make more progress:)


Another monster board, nice

To you have more details on how you split the power? The wheels are locked together? Or you have some kind of slip differential in the main gear box?

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Basically its just a steel rod going between the wheels, driving the rear wheels together. This will also be the case for the front once I receive the focbox from enertion.

This is how its connected now: IMG_0414 IMG_0415 Its a 3d printed adapter which mounts to the 4 holes on the back of the motor. The adapter has a 8mm hole which a steel rod goes in to. The steel rod is held in place by 4 M6 set screws. As the adapter is made out of plastic i had to use threaded inserts, which melts into the 3d printed adapter.

On the other side I made a simple plate which house a 608 bearing. This plate is necessary as the steel rod will wobble otherwise.

This method have worked fine for now, but I dont see it as a great solution. It was mostly made because I wanted to test the board.

This is how it will be connected in the future, final stage: 24 01 By doing a “2-stage-gear” you get the possibilty to do a very low gearing, like a ratio of 1:20 is no problem.

And the best part; you doesnt sacrifice any sort of ground clearance. I still have like 9cm ground clearance from the gearbox to the ground.

Currently I havent added the second stage for the gear drive, which means that I currently have a gear ratio of 1:5.625. Top speed right now is 55km/h which is way to fast. Will add the second stage once the needed parts arrive and make the ratio like 1:8, for 40km/h top speed.


Have you had any problems with the back wheels wanting to turn at the same rate during cornering? Also what batteries are you using?

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Nah, unlike what every other person on this forum says, you cant feel any difference with a locked axle. Not in snow, not in gravel, not even on tarmac. It works just as well as in a go-kart.

Batteries right now is just some left over lipos I had laying around. With 12s5Ah, I get like 4km range, which is like 50wh/km. I expect to see up to 100wh/km in loose snow when the board is all done.

Final battery is going to be around 1700wh, hopefully I will be able to do 20km in loose snow. :yum:


Very cool, now i really get what you talked about :smiley:

Nice to see the build thread. How your 6384 motors holding up? I had two of them already with broken magnets. One in cold conditions after spinning up on high rpm because of losted traction in snow.

For the focbox which is overheating, You could easy attach a heatsink from which you can find in electronic stores like I did on one of my builds. Just drill some threaded holes place some heat transfer paste between the stock heat think and the new one and screw everything together. Should help already a lot. image


I havnt had any problems with the motors yet, just the shaft coming loose once. It was an easy fix tho, just add some 648 threadlocker. I though about «battle hardening» them, but i dont really want to do this :joy:. We’ll see how they hold after some more riding first.

For the heatsink i havnt bothered too much with it yet, but I have designed a fat full aluminium waterproof heatsink. Just need to wait until Chinas holiday is over, and I will order a few (5).


I am also doing similar projects. I will use a part called Free wheel. I am hopeful that your test results are OK. 50%20PM 52%20PM 45%20PM


Interesting, does the free wheel work like a ratchet? Will the wheels still be locked together, or will they be able to spin at different speeds?

you have been making a sudden change of direction while riding. Perhaps you will experience locked axle. I try to overcome this by applying the free wheel diagonally. When the front wheel is locked, the rear wheel transmits power, and when the rear wheel is locked, the front wheel transmits power.

It is the structure that the front wheel or the rear wheel is locked depending on the direction of turning.

The free wheel behavior is similar to a ratchet.

I knew IT!!! Been banging on about this for a bit now and keep getting shot down with talk of one way bearings etc. While I was talking about it you did it. Lesson there somewhere.
note to self Get off your arse you old windbag.


Finally received my replacement focbox from Enertion, so figured I would try dual rear motors. This was actually my first time trying out dual motors on a e-mtb, and the difference in power is insane. Even though my power settings are pretty low aswell, only 40 batt max and 80 motor max (per focbox). :sunglasses: This thing does wheelies all the time at dry ground :yum: image
Still waiting for parts to make it 4WD, but I am almost confident that it will have enough power with the lower gear ratio, even with only 2 motors. I am aiming for around 100 amps batt max in the end, so ~10kW in theory. :laughing:


Sick board man! Where did you get the models for the Trampa board, and where do you have the batteries?

Great build :ok_hand:

The tires look so dope, did you swap to longer shafts on the trucks to fit the hubs?

@Sindre Thank you very much! :blush: I modelled the entire board (or atleast almost) in fusion 360, shoot me a pm if you want the files for the deck/trucks. Batteries are on top, between my legs, only some 220wh lipo atm though.

@rich Thank you, means alot when it comes from you! :star_struck: Swapping the axles for longer ones was my initial plan, however I was not able to get the stock axles out. Or atleast I didnt want to spend more time on it. So instead I 3D printed an adapter which mounts to the stock axles, but offsets the wheel with about ~50mm if i remember right. I will show with photos later :yum:

For anyone wondering why there have been no updated is because I am still waiting on some parts from China. I expect them to be here within a week, so there will be more updated soon :grin:

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Amazing! I need this in my life. To get through the Norwegian winter. How does it perform on ice? Looking forward to more updates.

@BearHere I tried it on some sort of ice track (dont know the english word), and while I was able to get some traction, it wasnt a lot. The board basically drifted 95% of the time, as there was no power at the front wheels. Keep in mind this was without ice spikes. According to Duffman they perform really well on ice with the spikes screwed in.