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Mini Monster Truck

April 10th, 2014 Leave a comment Go to comments

Simple model built for testing RC motors with low-weight vehicle. Features RWD and full suspension.


Completion date: 10/04/2014
Power: electric (Power Functions)
Dimensions: length 31 studs / width 21 studs / height 24 studs
Weight: 0.565 kg
Suspension: front – independent / read – dragged axle
Propulsion: 1 x RC motor geared 1:1
Motors: 1 x RC motor, 1 x PF Servo
Top speed: 11.6 kmph

The idea behind this model was extremely simple: to take my Trophy Truck, remove one motor and cut the weight by as much as possible. The resulting vehicle had better power-to-weight ratio, which is crucial for the LEGO RC motors, as they are known to perform best with low loads. To lower the weight, however, I was forced to give up the RC unit in favor of the Power Functions system. Thus the RC motor was powered by the 8878 PF battery via V2 PF IR receiver, which provides lower voltage than the RC unit does. Eventually, the model ended up being slightly slower, but it had fantastic acceleration and was very playable. Technically, it basically identical to the Trophy Truck, with direct RWD, no differential and independent front suspension with return-to-center steering. It used exactly the same wheels, and it was softly suspended, although the front suspension’s travel was shorter than with the Trophy Truck.

As for the body of the model, I wanted it to be lime, lightweight and robust, and it ended looking up like a souped up version of the LEGO 42027 set. The body was capable of surviving a turnover without any damage, and ensured easy access to the battery. I was somewhat concerned about the Servo motor being exposed from below, but it stayed safe even when driving through pools outdoors. While rather difficult to control, the model proved to be exceptionally safe and tough – it could drive straight through a pool without any electric elements getting wet, and any collisions were alleviated by the soft balloon tires acting like bumpers.


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  1. Sariel
    May 28th, 2015 at 18:29 | #1

    @mr J
    No and no.

  2. mr J
    May 28th, 2015 at 15:30 | #2


    can I get the instructions please?
    otherwise sell your car .. lol

  3. Sariel
    November 28th, 2014 at 18:43 | #3

    I think this vehicle is tiny and weighs almost nothing. There’s very little stress on the rear tires.

  4. EV3fan
    November 28th, 2014 at 14:33 | #4

    Hmm..the effect of the missing diff doesn’t seem so big in the video – is it because the abount of robber touching the ground is so low with these tires or because , due to weight shifting in fast corners , the vehicle is tilting to the side and thus the inner tire (rigid axle!) is being lifted off the
    ground? What do you think?

  5. Grzegorz
    October 17th, 2014 at 21:00 | #5
  6. Grzegorz
    October 17th, 2014 at 20:59 | #6

    Tu znajdziesz łatwo wszystkie częsci RC i całe zestawy. Na Allegro rzadko bywają wystawiane. A jak już to zaraz są kupowane.

    Sariel.. może jakaś instrukcja co do montażu tego MOCa? Albo przynajmniej rozmontowanie go na mniejsze fragmenty i pare fotek?

  7. andy
    June 25th, 2014 at 06:12 | #7

    if i were a pro monster truck driver, i wouldn’t ride that truck cause it would flip over every turn… or maybe you’re just a bad driver….. XD

  8. Sariel
    May 25th, 2014 at 05:56 | #8

    I think it actually improves sideways stability.

  9. Max
    May 24th, 2014 at 02:04 | #9

    Wouldnt dragged axle degrade preformance in the bends

  10. Sariel
    May 10th, 2014 at 15:05 | #10
  11. victor
    May 10th, 2014 at 12:31 | #11

    Hi Sariel.
    It’s a wonderful MOC.
    Can you make instructions please 😉

  12. Sariel
    May 3rd, 2014 at 09:33 | #12

    It;s just some song from YouTube’s free music library.

  13. Lucas
    May 2nd, 2014 at 03:29 | #13

    Awesome MOC! What song/band/music is that in the video?

  14. Sariel
    April 11th, 2014 at 21:52 | #14

    @Tobias Stanisfugl
    Yes, that was the remote.

  15. Tobias Stanisfugl
    April 11th, 2014 at 20:55 | #15

    Hi Sariel
    Nice design, what can one do with some bigger wheels and strong motors.
    But I had named it “Tumbler”, since its weight distribution makes it a little top-heavy, and the stiff high unsuspended mass rear axle leads to a sudden alteration to the vehicles dynamics, because the total steering radius immediately changes when one rear wheel lifts off surface.
    The driving dynamics of the Trophy was much more convincing seemingly on the videos.

    It seems on the video you have played and steered it whith the small dual toggle remote?

    Greets, Tobias Stanisfugl

  16. Sariel
    April 11th, 2014 at 19:21 | #16

    Tak, pojawiają się raz na jakiś czas.

  17. Pawel
    April 11th, 2014 at 18:48 | #17

    Rozumiem, że trzeba “polować” bo teraz ich nie ma, ale przepraszam że wątpiłem że mi odpiszesz.

  18. Sariel
    April 11th, 2014 at 18:35 | #18

    Polecam Allegro.

  19. Pawel
    April 11th, 2014 at 18:19 | #19

    mam 12 lat i na imię Paweł i jesteś moim idolem. Mam pytanie. Gzie można pozyskać takie silniki rc? Bo chciałbym budować takie rzeczy jak Ty.

  20. Sariel
    April 10th, 2014 at 23:54 | #20

    Live axle can twist to sides, dragged axle goes only up & down.

  21. Max
    April 10th, 2014 at 23:46 | #21

    What the differance between live axle and dragged axle… Or is there no differance ps nice pick in color.

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