[kicktail] Ursa Minor - Art on wheels

It started with the deck. Couldn’t help to get this beauty which gave me the excuse to start looking for the remaining parts and basically start another build.

So this build was not a departure from my last build but pretty much an improvement (as it seems) on it. While it is also a kicktail + GD + pneummies approach, I wanted to try the Moon AT GD and Boardnamics BN270 trucks instead of 3DServisas which I tried last time.
Both Moon and BN are for me an example of top quality and affordable prices which is the kind of thing I’m interested as a builder.

This was also a very simple build in terms of extra components. No Davega, no lights, etc, just the bare minimum. It does have a battery capacity display though :crazy_face:

Riding experience

After riding this thing a couple of times I have to say it turned out even better than I expected. The bigger Evolve 7’’ tires offer a fantastic grip and confort. Also, this board is running on a 4.89 gear ratio with 130kv motors… the torque is f* unbelievable!!! I cannot give full power to this thing without doing a wheelie even with my weight all on the front.

Actually the setup is a bit extreme as I have a top speed of only 35 km/h. I’m loving it as I ride mostly in the woods and this baby feels like a rocket even on the steepest hills.


  • Kicktail 38’’ stiff deck: Riviera Ursa Minor
  • Wheels
    • Evolve 7’’ tires
    • MBS Rockstar II hubs
  • Motors: APS 6384 130kv sensored
  • Battery: custom by @pmg
    • 12S3P 21700 Samsung 40T
    • Daly BMS
  • Gear Drive
    • AT straight cut Moon GD
    • Gear ratio: 44/9
  • Trucks: BN270
  • Focbox Unity
  • Flipsky VX1 remote
  • Weight: 14.2 kg
  • Maximum speed: 35 km/h


Moon Gear Drive impressions

Loved the simplicity and quality design of this GD. Also liked very much the fact that it is possible to remove the motor with the pinion in case one wants to swap it, unlike with 3DS GD.
Clearance with 7’’ tires is enough, would be great if it would be even smaller to handle 6’’ tires better.
The sound is amazing, I tested it with no lubing and it seems like a race car. It’s crazy compared to 3DS which is totally silent.
Only problem I had with this GD was that the fixed holes for 9T had too much of a backlash. Was not a big deal as I could tune it well with the adjustable slots.

Battery building



Used Lucid clear grip spray to preserve the beautiful art work of deck. Because I used the heavy grip variant, it was difficult to make it stick so I had to use a lot of glue and a brush instead of just spraying it as recommended.

Filled the wheel wells with wood putty (thanks to @Riako for the tip!), to recreate a flat surface for the enclosure and avoid water ingress. This allowed to move the enclosure more to the front gaining more clearance on the back between the motors and the enclosure.

I used the battery capacity meter design by @chberne along with this meter.

For the risers I designed a slightly angled riser with tunnel. Can share the design if someone is interested.


The enclosure is from @EboardSolutions. Those “giant washers” are brilliant and were created also by Frederic. I though about adding a fiberglass reinforcement on the ABS enclosure but ended up not doing it, in the motto “don’t fix what it ain’t broken”. I want to find out if it handles the weight just with the help of the metal strips.

To seal I applied a Crown rubber strip SRS136 15mm x 8mm om the enclosure and 10mm foam on the deck. Made the holes first with a punch tool, very important.

On the front installed an XT30 for the battery meter and on the back there are two MR60 for the motor phase wires. All fixed with epoxy.
For the sensor wires I didn’t have space for one of those 6 pin round connectors which tend to be very long, so I ended up using a junction box gasket. Made a 4mm hole first with the punch tool.


Made extensions cables with MR60 connectors and added 13mm PET braided sleeves for cable protection.
Because these motors have an open can I used 3d printed covers from @Pryside. Also used a bit of silicone on the wires hole. The phase wire PCB is already conformal coated so I didn’t do nothing there.


After I fixed the stock BN axles with green loctite I realized they were to short and had to take them out. I got them out with the help of a propane torch and used 10mm shoulder bolts with 90mm length as a replacement.
Got 10mm spacers: 12.5mm long between GD and wheel and 22.2mm long for the Rockstart II hubs.

Many thanks to @b264 for the waterproofing ideas, @Athrx, @ProfoundMagician and @Minimadness for the help with the shoulder bolts workaround and the vendors and users of this great community for all the help and inspiration.


Looks like it would be alot of fun blasting off of curbs onto the street from the sidewalk when there are too many people in the way


Great build! That’s a sweet deck

Would love to hear more about your gasket, connectors, pass thru, etc. Also, where’d you source the enclosure mount plates (aka giant washer)?

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How did you end up securing the shoulder bolts? Is the pressure with spacers enough to clamp them securely?

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Definitely a pleasure with this deck. The tail is a bit short but still totally usable.


I’m guessing the tail is the best place for rear foot placement so not to scrub the wheels

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For now I just applied a good torque (metal spacers are there) and didn’t put any loctite. Will probably put some blue loctite after some rides.

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My pleasure, will give detailed info.

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Exactly, I was a bit worried about that but it felt comfortable to have the foot more on the rear.
I don’t have this problem with 6’’ tires but with 7’’ it’s definitely there.

Man, you make me want that deck. 38.5"x9" is a great size.

Lol @ the wheel cutouts vs your pneumies


A worthy candidate for the legendary downhill decks club.

Would love to see what you would do to her :smile:

Nice build!

I wonder how it would be possible for the 9t predrilled position to create too much backlash? Did Moon comment on if this was one-off fluke, or if all batches had this problem?

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Might be a fluke because it seemed way off


Could I get a better look at that battery capacity meter? Is it a regular battery meter in a 3d-printed housing? Or something fancier? Looks good! :smiley:

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It’s this one by @chberne, I love it!

It’s a very affordable solution as the housing is just 3d printed and the meter costs about 11€. I bought it on Amazon: https://www.amazon.de/-/en/gp/product/B07C2NJL2V/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

One thing I also like about this meter is that it is possible to turn it off to avoid battery draining.

I’ll write a “details” section on the first post where I’ll add this and all the stuff I can think of that might be relevant.

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Just added a details section in the build post and included this info. Guess it’s a work in progress but it has already some info.


(forgive the lack of helmet, was just making a pause and playing around)


This (plus maayybe field weakening if I get desperate for a little more speed) looks like my ideal build to be honest. How have you found it since April?

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I’ve sold this build to a friend right away so I didn’t ride so much unfortunately… I’m still riding my other build with the Lush 3D though.

Nonetheless, these are the points that could be improved I think:

  • Not sure about the 7’’ tires, might go back to 6’’. Both have advantages and disadvantages.

  • Personally I like a little bit more tail on the deck. Decks like the Lush Machine 3D or the Zenit Marble 38 are really good, although not so beautiful :slight_smile:

  • The enclosure is too narrow. This is fixed with the Marble + BB enclosure combo

Otherwise I’m really happy with it.

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