[Tuning Stage] III:THE EMPRESS | Apex Bro / Airs / Chain Drive | 6384 140 kv 5:1 | 12s2p P42A | DV6 | | 8" Rockstar II

I am finally getting started on my first emtb build now that I am finally settled after my move!


Upright: Beauty, nature, nurturing, abundance
Reversed: Creative block, dependence on others

Now I don’t actually know almost anything about tarot cards, but I saw the description of this card and thought that it was just so apt for my goals and experiences so far with this build. I scrapped quite a few ideas that I originally wanted to tackle for this build just because the time/payout just didn’t add up for me. That’s where the creative block/dependence on others come in. Inspiration from other builds here for the first, relying on all the information I have gathered over my time here for the second.

The general goal for this build is to have a more lightweight build that I can take to skateparks/pump tracks/park trails, and then have a removable range pack that I can use whenever I need to go on longer rides. I am still working on how I want to setup the range pack but for now I am going to be focusing on the core setup for the build. Most of my rides are generally within 10 miles so I figured a 12s2p will most likely cover that use case. Plan at the moment is just to have an XT90 available to plug into (with both batteries at full charge of course) that is panel mounted to the enclosure.


NESE Modular Jumper @sleepless
Gathering Storm @Pedrodemio
The two above for their modular batteries

EVOLUTION @ducktaperules
Was originally going to make an external ESC case in the middle of the board akin to this one but ended up deciding against it when I opted to go 2WD rather than 4WD. I still absolutely love the main ideas behind this one though.


@ApexBoards :

  • Apex Predator Haero Bro
  • 6384/140kv w/ circlip cutout
  • Chain Drive 5:1 Ratio w/ mounts
  • Apex Airs

Pulled these parts of of the Dylan Warren II prebuilt I got from them during black friday sales, the DWII was a bit too stiff for my liking.

  • Rockstar II
  • 8" Tires
  • Matrix II with either yellow or orange shockblocks
    Swapped with airs due to compatibility issues with the chain drive


  • 12s2p P42A brick pack (couldn’t pass this up on sale for $200)


  • Hoyt puck with Poastmote shell, what I use on my current board. Just got a second receiver.


  • TENKA, I know the sentiment around these is that they are generally garbage but I bought this before I joined here and didn’t know anything about the reputation of the company. I want to put it to use if I can rather than just never use it. If it shits the bed on me I am planning to replace it with a DV6 or similar.
  • Decided against even trying to use the TENKA, will save it for a low power board or selling it for parts. Bought a DV6, I want to do this one properly.


  • Harbor Freight Apache 1800, the pack and ESC just barely squeeze into this with enough room for electronics


  • Metr Pro, I intend to use this to switch between power profiles once I figure out how I am going to attach the second battery pack.

Next Steps:

Actually starting the build process, I’m pretty sure I have gathered all the parts that I need at this point and I think I’m going to start with the layout of the enclosure.

As of right now I think that I am going to orient it horizontally with the phase/sensor wires running below the battery into MR60s that are epoxied into the enclosure. Using JB Weld steel at the moment unless there are any other recommendations for something that would better suit this use case. I was originally going to go with 2 PG11 glands but I think they are going to end up being too thick to fit properly. All of the phase/sensor wires are going to run under a custom rubber foot pad.

It actually does baaaaarely squeeze in there

I also need to figure out how to shorten/seal the pressure release valve of the case as I don’t really want the exposed metal to be rubbing up against the side of my pack.

Loopkey and second battery plug are going to end up either being mounted to the underside or the lid, leaning towards underside at the moment. Might do underside for the second battery and lid for the loopkey. Don’t think I’m gonna bother with a regular switch on this one, loopkey should be enough. I also need to draw up a wiring diagram before I start soldering so that I make sure to keep everything sorted properly.

Also I’m guessing I want to solder up all the connections before epoxying in all the connectors? It seems like it would be a huge pain to try and do that afterwards.

I’ll move on to setting up the drivetrain after I sort out all the electronics. With how easy Apex made it to assemble everything using circlips I’m hoping that portion of the build won’t take that long.

If anyone has any suggestions on improvements/modifications to the plan that I might want to make please feel free to comment! I want to start this build soon but want to make sure I’m not missing anything obvious before doing so. I made quite a few mistakes on my first build and want to make sure I don’t make them again here!!


Awwwwesome! I know you’ve been working towards an eventual eMTB for awhile now. Happy to see it coming together. Looks like it’ll be a classic. Interested to hear the report on how the new Chain Drive feels.

Random collection of thoughts:

My enclosure is way bigger than I’d like, but NESE so :person_shrugging:. That said, it almost goes all the way to the MBS straps and I still never notice it. It’s mostly personal preference / aesthetics, but I vote lengthwise. Also think about if you’ll want to open it while strapped it - lengthwise will be a little easier, although again not a high priority concern.

Are you going with a heatsink? No matter the esc, I would highly recommend it when you’ve got all your electronics in one case. If anything overheats, you’re heating up your battery. Bad news bears.

If it doesn’t physically get in the way, you could easily epoxy over this. Or take a dremel to it.

The captured loopkey design I’ve been working on is basically done, pending test fit, so I can toss that your way if you’re interested in it and want to play with locations.

On this… do you, but my experience has been one of repeatedly moving connectors, redo-ing connections, and constantly fighting imperfect wiring lengths. Don’t underestimate the room wiring takes up - too much is a burden, too little risks pulling and unwanted forces.

If i were to start my build from scratch, I would plan and lay out everything before wiring anything inside the enclosure. Including extending phase & sensor wires, mounting a heatsink, fitting the pack(s) (do you want a strap or some sort of method to keep the battery in place? how are you going to suspend the battery above those floor mounted MR60s?), mounting remote receiver, mounting metr, installing foam padding / rubber pad / velcro. Do all that as far as you can, and check clearances/fit before you start soldering and installing connectors. Much easier to map out correct wire lengths that way. Even the orientation of the esc will change how much wire you need. If you’re interested in lights, now is the best time to get a buck and plan for that space and wiring. Also can’t uncut an enclosure hole…

Also this would make a super dope vinyl wrap on that haero:


I cut off the excess with a dremel. I probably could have cut or ground off a bit more, but since I have a bit of foam on the sides it’s not a huge deal.


Really excited to get this one going!

I was thinking horizontal and then making the eventual top box look like sort of like one of those winter hats? Like this:

I guess that could really work either way, I mostly just need to see what hat config works the best. I’ll probably have to throw together some dummy cad for it.

Yes I am, had a small debacle where UPS marked my package as delivered but lost it. Hopefully that will be resolved soon.

Think I’m just gonna tighten it down and do all of that :rofl:. Dremel the shaft down when it’s fully tightened then epoxy over the sharp bits. Not sure how this will affect the waterproof-ness but hopefully not too bad.

Definitely going to take you up on that one, design looks slick as hell.

That’s exactly what I was planning on doing. I am going to be soldering the finnicky bits with wayyyyyy too much extra cable length, temp tacking things in the enclosure with some removable mounting putty, then cutting to length and finishing the solder connections.

I was planning on filling any of the void area with either a 3d printed riser or dense foam, leaning towards the latter for the shock resistance.

Not at the moment as I very much worry about fitting that in the enclosure, as well as the fact that I already own shredlights and may as well put their intended function of being able to swap boards to use :crazy_face:

I really like that design, hadn’t really considered doing a vinyl wrap at the moment but you are making me heavily consider one.

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Def gonna try to dremel it before anything else, hopefully I can get it short enough to be able to be closed while not sticking out of the thin foam layer I put for cushioning.

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Yeah dremel should be just fine, makes pretty quick work of the screw with the cut off disk. I finished it off with a file so it’s smooth, and you could make it shorter than flush and loctite it in because you’ll never turn it so there’s a lot of tolerance for the actual cut.


I got mine printed in Avery MPI 1105 from weprintwraps.com and it’s held up surprisingly well. $20 for the vinyl + $30 shipping. Not too bad to experiment. There’s probably a local car wrap shop in Austin that will do it. ~30 minutes to install and smooth bubbles/wrinkles beats a real deck skin job for ease any day.


I think I may end up going with this one:

The original looked like this:

I like the original a lot but really wanted a black background. Inverted the colors and did a couple other little tweaks and am really happy with the result. Plus this one is a bit taller so hopefully it will fit the length of the deck well. Looks like there are a couple local vinyl places near me so I’m gonna get a quote and see what the pricing is like.


Some small updates:

  • Bought a DV6, I really just want to do this build properly and don’t want parts that I’m gonna constantly worry about breaking.
  • Started assembling the drivetrain while esc is in transit. Trying to debate if the phase wire clearance is enough, my gut says no.

    Maybe I could take a heat gun to the heat shrink to see if I could soften it and mold/angle it out of the way? Worst case I just rotate the motors, I just wanted to run the wires along the trucks.
  • Fixed the pressure release valve on the Apache case. Took some pliers and ripped off the clip that was stopping it from unscrewing and then chopped the screw with a Dremel. Sits nice and flush now:


Yes, it’s the glue that makes it really stiff. I just cut it off but that should be fine


I’d say you’re good. You’ve got the braided PET as well as the silicone to protect the wires and the socket head isn’t sharp at all. You can also visually inspect it very easily.

GLWTB :call_me_hand:


Welp, looks like I’ve already ran into a few incompatibility issues. I guess this is to be expected with things coming from so many vendors but I’m reaaallly not sure how I’m gonna sort this one out.

Even if I bought another bearing that fit on the raised portion I would still be short about 8mm. Has anyone ever successfully removed these axles? Because that is really the only way that I can see using these trucks in the long term.

I am also now realizing that I am an idiot - Straight from the Apex website:
“We know people will ask, but unfortunately the MBS Matrix II is not compatible with the Chain Drive. This is due to the stepped axles, which are not compatible with our bearing layout. Hopefully this changes for Matrix 3. If there are any other adapters that people want then let us know and we will see what we can do.”
Pretty sure I took this to mean that the mounts were not compatible with the Matrix IIs, and not the sprockets. Which was just a very poor assumption. If I had thought through the assembly process at all I would have realized this.

To be fair, I already had motor mounts so I’m pretty sure I only went to the page for the sprocket kit, not the full product page for the chain drive when purchasing. The sprocket kit page does not include the disclaimer that the chain drive is not compatible with Matrix IIs @ApexBoards.

Looking like I may not be able to use the parts that I was intending after all mostly because I’m shit at reading comprehension.

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I wanna say it’s all about the DIY journey… but shit like this is incredibly frustrating and bloody expensive to boot. Tbh though, I haven’t had even 1 board where incompatible components haven’t plauged the build.

The most economical solution is to sell the chain drives and buy some pulleys and belts. If your budget can take the blow, however, sell the matrix II’s and grab a set of Apex Airs and pimp that ride


My wallet says to buy some pulleys and call it a day, but my gut really really almost bought the airs combo when I got the sprockets in the first place so I think I’m most likely gonna pony up for them.

My overall main Esk8 goals are to have an off-road/jumper build (this one) a street build (My first one), and eventually a stealth urethane build. And I really wanna do things properly this time, even if it’s gonna end up being more expensive overall.

Definitely gonna be offloading some stuff soon to help pay for this :sweat_smile:


airs will do great on an offroad exclusive board


Im sorry to read your issues here, I will rectify that on the website now. Thanks for flagging it with us.

We will honour the airs/chaindrive combo price and send you a custom invoice now. You are going to love this setup dude.

edit - invoice sent :slight_smile:


Invoice paid :slightly_smiling_face:

Looking like this build is getting an upgrade! :muscle:

Also if anyone is in the market for matrix IIs + mounts hmu :sweat_smile:


The DV6 is finally here! Now I’m starting to plan out all the electronics and wire routing. I also needed to drill some holes in an mboards heatsink that I had leftover from my last build (didn’t really feel like I needed it with the temps I got). After a while of fiddling with my non-3d printer to get it to print to the correct scale I almost drilled all the holes in the right place first try:

3/4 isn’t too bad anyways. I’ll probably spend some time tomorrow trying to ream that out to see if I can make it work. If not I’ll have to use the drill press at my work to see if I can shave off just a bit. Thinking I’m not going to route out so that the screws mount flush, I don’t really think that I have the equipment for that at the moment haha.

Trying to think about how I am going to do the panel mounted XT90 for the other battery, as well as the loopkey. Also @sleepless how is that captured loopkey coming along? I need that in this build for sure!

Thinking that the external battery port is going to be on the side and the loopkey is going to be on the top of the case. For the external battery port, how important waterproofing that? I am planning to seal the gap in the XT90 with epoxy but all I have protecting the contacts is going to be a TPU cover/plug. Is that generally considered enough?

Charge port is most likely going to be stacked above where the battery xt90 is or on the side of the case for easy access. I’ll make a shitty mspaint diagram at some point once I get the DV6 mounted to the lid. That one is going smack in the middle because aesthetics reasons. It just fits the space too perfectly to not.


Captured Loopkey - Mount V5C.stl (368.3 KB)
Captured Loopkey - T-hook v3.stl (780.5 KB)

Was working on some alternative pull styles and got caught up in crunch time at work. But give these a look/print and let me know what you think. I need to adjust the fit slightly - i think it’s a little loose. This one is the absolute minimum size version, so you’ll need to shave the pins on the female side.

Also, my trick for transferring drawings onto raw material is to use an automatic (spring loaded) center punch to mark those holes through the paper. Makes an easy indentation to start drilling so your bit doesn’t walk. Pick up one of these guys for next time:

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I basically used a janky version of that by taking a tap that I was never gonna use, lining it up, then giving it a whack with a hammer :rofl:

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