DIRT MACHINE | Trampa Holypro 16 ply | Vertigo trucks | Superstar hubs | Unik Polaris 6374 150kv | E-toxx black direct drive | Vesc 6 | 12s

First of all I want to thank all forum members for the big inspiration and great support, I love this place!

This is my third build and I’m an esk8 addict. 2 years ago I started with the intention to build a cheap longboard but ended up with 3 builds so far…

The evolution of the MountainFOCer (now called dirt machine)

I built version 1 of the MountainFOCer last summer and actually are working on V2. I describe here what I’ve done so far plus what I’ve changed and why. Also about real life experiences with the setups and more. For V2 there will be updates from time to time, so stay tuned.

V1 setup: trampa holypro deck 16ply | vertigo trucks 136kv 6364 sensored trampa motors trampa urban mounts dual esk8 4.12 controller DIY enclosure 10s 10Ah Turnigy Graphene Lipo bypassed 10s BMS for charging 8” trampa treads (hard compound) on superstar hubs 14T / 66T pulleys anti-spark switch with fuse

Range: max. 23 km / 14 miles Length of cables from battery to capacitors: 28 cm / 11 inch Length of phase and sensor wires: about 85 cm / 33.5 inch

But now some general details about this build and V1:

First thing I did is to get rid of all bling bling parts because I don’t like it shiny, it must be black. I went to a local shop for black anodizing and love the result.

The Trampa motors also got a special treatment with carbon foil, black bolts and black metal mesh against debris.

The urban mounts are sturdy and the grub screws keep tight. I like the look more than the pro mount but the disadvantage of an open belt system is that all that debris enters the drive system. I damaged some belts so far due to stones between belt and pulleys or by hitting the ground with belt/wheel pulley.

I tried idler pulleys on the slack line and it worked well but the tiny M4 bolts get loose and bend quickly, changed to M5 bolts but am not happy with the durability so I dismounted it. The motor mount is long enough (axle to axle distance) for most cases, but on hard braking the belt can skip, I like to have the belts quite loose.

The enclosure was bent from an 0.5mm steel sheet and was a lot of work but it did the job. Bottom and top are 4mm plywood. I would use 0.8mm -1.2mm aluminium sheet if I would do it again. The goal was to have battery and Vescs in one box in the middle of the deck which I like more than the look of 2 boxes. In the end I changed my mind because it was impossible to swap or change batteries with this setup.

Outside I put carbon foil and inside some pieces of foil I had to insulate the metal.

A short story about my vesc disaster. I started with 2x flier V4.12 but the hall sensor ports were not working so I switched to 2x Maytech V4.12. I realized that BLDC hybrid mode didn’t help with cogging at all, just a better control at low speed, that’s it, but feels like unsensored. After many different trials I knew FOC would be the only solution in my case. Bad that Maytech don’t run in FOC that’s why I ordered 2x esk8 4.12 controllerand finally it performed as I wanted, smooth startup without any cogging! Well, because I work on 2 builds (the Urban FOCer is not finished yet), I needed another 2 vescs for use in FOC, so I ordered 2x esk8 controller 1.1.

That should be enough vescs for a long time and I was totally broke. 2 weeks later my MTB didn’t run anymore and I was sure that I fried the vescs. That’s why I begged Frank to sell me 2x VESC 6 for a discounted price, what he fortunately did. 2 days later I realized that a solder joint of a phase wire was disconnected (couldn’t see it through the wire mesh) so all good, after resoldering everything was working again. Because of VESC 6 I sold all V4.12’s I had, only kept the esk8 1.1 controller for the Urban FOCer.

I started with 10s 10Ah Turnigy Graphenes (6s+4s in series) with bypassed BMS for charging only in combination with a 42V Li-ion 3A charger. Placed in a Lipo safe bag with some foam and wrapped in fabric tape.

Everything was working well until the day I forgot to switch off the board after a full discharge, 28 hours later the cell voltage was 0.887V. One more reason for V2 and upgrade to 12s…

As remote I have the steez but had some problems with scary dropouts in the beginning. The receiver was too close to the metal and after reposition the issue was gone.

I use motorcycle 5g adhesive lead weights against valve/wheel wobble and it works really nice , big up @whitepony AFAIK the first who tried this technique on MTB hubs. It is a big difference. After 600km some weights are missing, in the future I’ll take pictures of all wheels so I know where to add missing weights without balancing again.

First I used the 15T pulleys but after a couple times of reassembling the grub screws were stripped and got stuck. Thread locker on the grub screws was not enough, it came loose very often because of the play of key and keyway. I ended up with using a special non-permanent thread locker for shafts for the new 14T pulleys. I put plenty of it on the motor shaft and key and since a few hundred kilometers it holds up very well. It’s ridiculously cheap, both thread lockers are from hobbyking.

EDIT: This HK thread lockers are too strong, it needed heat to remove the pulleys, I switched to the genuine Loctite.

I use the 8” trampa treads in hard compound. Because of more tear on the rear tires I swapped the rear and front tires after 300km (186 miles) and had another 300km. In future I’ll wait until the rear tires are worn out, then replace the 2 and the next time all 4 and so on, less work.

What really sucks is a puncture, I had 5 within 600 km (373 miles). The tires had no visible damage and there were no stones inside the tire, no idea why this happened. I fixed the tubes with bicycle repair kit and they last so far.

I love the fact that I can ride without taking care of the battery and electronics, for MTB top mounting is a must IMO, it’s ugly but rocks! Here you see what happened to my nice Trampa sticker and why I enjoy top mounting

One Video tells more than 1000 words and pictures, so I uploaded this video for comparison of bldc and FOC mode. In the beginning you can see the annoying performance at startup with hybrid BLDC. Sorry for the length of this video, better skip sometimes :wink:

Meanwhile I’m working on the second (and hopefully last) version of the MountainFOCer and will post some more details soon.

Changes in V2: dual VESC 6 E-Toxx direct drive separate DIY box for electronics at the tail of the deck 12s bestech BMS for discharge/charge 12s 8Ah Lipo (+ 12s5p 15,6Ah Li-ion) Peli case for swappable Batteries direct fet anti-spark switch


Yeah it’s time to get serious! I like you enclosures and the Motors :sunglasses: And you should really think about opening a museum for all the VESCs :smile: Curious to see which color you choose for the direct drive :smiley:


Hehe. I sold most of them but I have this picture for the museum (but one was sold already when I took this pic)

Guess which?

Shipped one vertigo hanger to @nowind for machining. Can’t wait to receive these beauties :heart_eyes:


Received the direct drive today and am happy, it’s f****** sexy! @Nowind = Nodirt = Noproblem

Also there is some progress on v2 of the MountainFOCer Hexagon news, no comment………

some hours later…

FInished my first 12s battery “brick” with bestech BMS for discharge/charge with 2x 6s 8Ah 15C Turnigy Graphenes. Furthermore I want to build a 12s5p Li-ion 15,6Ah with VTC6 cells within the next weeks/months for more range and easy swapping.

Some ABS for protection

For now I’m going with a PeliCase 1150 bolted to the deck with some rubber washers for both batteries but I don’t like the bulky look at all. I think I need to change that but that’s not first priority now, I need to ride first

I’m a bit jealous when I see all you guys with 3D printers. I have to do it old school style and bent an aluminium sheet for the enclosure. The Vescs are bolted directly to the aluminium enclosure so it should help with heat dissipation. I tried it with a cardboard model first.

Added 3x M4 threaded inserts for the enclosure.

Glued all open edges, added some insulation and carbon foil.

It is really tight inside with 2x VESC6, 1x @goldenHusky Direct FET Antispark with LED switch, 1x HM-10 bluetooth module, the huuuuge steez receiver (I had to remove one port on PCB) and all the cables. No more space left, hope the receiver works properly at that given position.

I’ll add a silicone gasket between the aluminium and the ABS cover for splash proofing. When I finally know the length and arrangement of the phase- and sensorwires I want to seal the cable feedthrough with silicone, too.

That’s it for now, hope to ride again soon, it is 4 months ago…


Today was my first test run with 12s and VESC6 :metal: I kept the belt drive because I wanted to feel the difference compared to 10s and V4.12 with the same drivetrain first before I mount the Direct Drive.

I use the @Ackmaniac App “VESC Monitor” which worked flawlessly. Last summer it didn’t with new FW but now it’s perfect (well, I would prefer a dark theme).

To be honest, I thought there is more difference in power delivery when using VESC6 but there is still a difference. On start up it’s the same but when hitting full throttle later it feels like I get more or faster power. Everytime hitting full throttle I had between 70A-98A motor current and max. 59A battery current. I was not nice to my MTB but when I came home the temperature of the Vescs was 17.5 degrees (and 29 max), I like the aluminium housing and also the fact to have reliable 12S FOC.

These are my settings in VESC-Tool for each Vesc (with 2400W 136kv motors) Motor max: 50A Motor regen: -25A Batt max: 50A Batt regen: -15A

I get a top speed of about 44 km/h with this 14/66T setup, but counted with a wheel diameter of 190mm, none of my tyres are real “200mm”.

I removed the dampas on the front truck and kept the yellow dampas on the rear truck. It’s really nice to ride, feels good. I’ll see how it’s gonna be in heavy offroad conditions if it’s too loose but carving or u-turns are much easier now.

Next thing is to switch to direct drive. Unfortunately it’s a bit cold outside, can’t wait for spring time!


I like what i’m seeing! Already suspected that there isn’t that much a difference in the feel between 4.12 and 6, but 6 should of course be more reliable in 12 FOC which is also nice when riding. Less worries and all.

Also curious about the tires though i don’t have high hopes for them :sweat_smile:

I might try removing the in the front as well, sound promising. I don’t like jumping around everytime i want to make a somewhat tight turn.

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Yeah these cheap ones probably won’t last long but I felt not much difference during riding, only the sound. They are thin and very soft compared to the genuine ones.

The ultimate turn you could get without springs :joy:

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Maybe when i’m planning the next roundabout-only tour :laughing:

I couldn’t find a replacement shaft for the trampa motors and don’t want to cut the original ones so I decided to get new motors and maybe sell the trampa’s including drivetrain.

Received my (frozen) parcel from Unikboards today, really nice guys and good service Ben and @okp!

They fit soooo nice, it’s like one unity :heart_eyes:.

I have to rename this build because with sealed drivetrain and motors it’s more a dirt machine than a MountainFOCer, also there are not too much mountains in my close area :laughing:. I hope the motors don’t get too hot in summer (BTW today it’s -11 degrees, can’t wait for spring)

The weakest part right now is the vesc enclosure because it’s not waterproof yet, especially the upper shell, I have to change that.


It seems like the snow is gone and I want to ride :stuck_out_tongue_winking_eye: Mounted the direct drive, looks so sick and can’t wait to ride the machine.

Unfortunately my vesc enclosure is too wide for this drivetrain so right now I’m working on a new one made of 2mm ABS, so much nicer to work with. I’m no boss in thermoforming that’s why I bend it with a heat gun at 250 degrees, easy. The new enclosure will be much better than my old one, also better sealing and stress relief on the wires so they can’t move inside the enclosure

Glued the edges and added some plastic angles for reinforcement of the structure and drilled 19 holes which is so easy with ABS, would love to drill more :laughing:, aluminium was a pain. Now it’s time to bend the upper lid and resolder almost all connections.


Finished the enclosure, had to enlarge the inner height from 30 to 35mm to fit all parts, maybe I need to make a new upper lid but fore sure not now :laughing: . Between both shells I use a thick flexible foam sealant, forgot to take pics. The LED switch for the antispark was too big that’s why I use a different waterproof switch and an additional red LED as rear light plus this way I can’t forget to switch my board off again :wink:

I had to remove the wire mesh on the phase wires but am happy with the nice cable grommets, the wires can’t move which is perfect and it’s almost waterproof.

Unfortunately some snow an frostiness is back but I have the feeling I can’t resist to test it anyhow. I’m too excited to feel the new drivetrain and motors :grin:


I like what you did with the box for vescs!

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Thanks @Acido, it wasn’t easy to fit everything inside and the enclosure isn’t perfect but hey, it’s custom made. I couldn’t find a box with nice dimensions, the one from UK is only 8,9cm in width. Mine is inside 12cm x 14,5cm x 3,5cm.

I had my first test ride today but unfortunately only for 2-3km because one spring retainer of the front truck broke, i think it happened because I crashed into a tree but I’m not sure.

But what I can say from this short ride is that I’m quite happy with my new parts. @okp these motors are powerful and good looking, I like them. @Nowind the direct drive is genius and the free coasting epic in comparison to belt drive. Maybe it’s only in my head but It feels like the MTB rolls better with attached drivetrain and motors than without :laughing:. The only downside is the noise, my dirt machine sounds like a machine now. But the advantage of the noise is that 100% of the people turn around even when I’m far away and hear I’m no joker and step to the side. I’ve never had this experience with belt drive and FOC that’s why I thought about using a bicycle bell but that’s the past.

It is so great that I can lean the board against a wall without fixing it :sunglasses:

Here a short part of my very first test ride with telemetry data. The quality is bad, the goal was to monitor the data. The video starts with a speed wobble at 44km/h (I think I’ll use my dampas again on the front truck, too spongy) and ends with a crash. I forgot the first rule: Always check the terrain BEFORE you ride there


That should not happen

Also that should not happen after 600km :face_with_raised_eyebrow:

Í need even more spare parts than this, this are my spare boxes, it’s ridicolous

I have 1mm, 1.5mm and 2.5mm bushings but no 2mm. I had to disassemble my urban carver to get some 2mm bushings, need to order some.

Today was another reason why I have all kind of spare parts. Imagine I have no spring retainer at home, then I would have to wait 1-2 weeks without riding. It happened to me 2 years ago in summer that my remote was broke and I couldn’t ride for several days before I found an ugly massive remote on ebay. Then I had to wait for an additional proper remote to arrive. Of course I have a spare remote. The worst case for any esk8-er is a board which is not running.


What’s up with the different sized bushings anyway? Haven’t looked deeply into it yet, but it appears there are different sizes for the same trucks depending on tolerances?

Direct drive indeed does sound loud. Don’t want to attract any unnecessary attention from hunters/police, as both tend to be assholes in Hessen… The former being awfully afraid of me spooking their game. Sticking with belts, though the maintenance free direct drive does sound like a dream.

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Hangers and baseplates have tolerances that’s why there are different bushings, only the thickness of the base differs. For example standard size of bushings seems 2mm. If I would use my spare hanger I would need different bushings, sounds complicated :laughing:, easier to explain with pictures:

First you measure the outside of the hanger without bushings

Then you measure the inside of the hanger

As you can see in my case there is 4mm difference so 2x2mm bushings fit perfect. There are also bushings on the baseplate but the size does’nt matter, usually they are 2.5mm and black. The 2mm bushings are grey.

Where I ride there is no police, I wouldn’t use it in public places and try to avoid streets and pavements. Do you mean hunters because there are animals which sound like a direct drive :rofl: or because they want to catch you? I would say “catch me if you can”


Thanks for explaining. Time to order some replacement parts.

Regarding hunters, they would complain about disturbing nature. They themselves drive around in jeeps. At my current skill level, they still keep up with me.

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Run them overwhey they get out of the jeeps Problem solved :wink:


That’s a good idea :stuck_out_tongue: Building a second board for my wife, which should be a bit louder and safe. I think direct drive is the right thing for her.

It took me some time to get used to the drag and instant slow down of belts when you let go of gas. The sudden jolt would throw her off for sure.

We will both go on a MTB course (for me personally, learning how to brake/slide). Hopefully, I’ll feel as Conformable as this guy at some point. Those pussy ass hunters in their jeeps would not be an issue :stuck_out_tongue: