[MOC] VW Beetle Baja Bug with Buwizz

[gyenesvi]

Hello Eurobrickers!

I am finally ready to present another long overdue model I built last year: a VW Beetle Baja Bug. This one was built for the 2025 Buwizz camp's buggy race, which was held on a grass track with artificial wooden ramps to make the models jump. The rules stated the model had to have max 82mm wheels and max 2 drive motors, and had to be an RWD buggy. I quickly settled on the idea of a Baja bug, because I find their looks pretty cool, and the bug shape seemed light weight with most of the heavy components in the back, which sounded like a good idea for jumping. Furthermore, I wanted to try building a trailing arm suspension using two Buwizz motors (which for me are the only meaningful way to use the buggy / Buwizz motors in a 4x4 off-roader, due to their awful form factor).

It took me quite a while to make a proper video of it, because I was using my phone both to drive and to shoot the video at the same time, and I had to develop an app that can do both simultaneously, and integrating video stabilization got more difficult than I expected, but finally got it working.. Anyway, let's see that obligatory performance video :)

 

 

Features

• Independent front suspension with bug-like portal arms and positive caster angle
• Independent trailing arm rear suspension
• Rear wheel drive
• Complete interior with two seats
• As you can see, bug-style exterior :)

 

The two key components I needed to develop was the trailing arms and the front portal arms. The rest sounded simple, the abdomen (rear section) seemed like a good place for the Buwizz unit, which left most of the center empty for seats and interior.

Trailing arms

For the trailing arms, using the output of the Buwizz motors is unfortunately not possible, as it does not provide enough torque for off-roading on grass with such a heavy model; it would shut down the Buwizz unit almost immediately. So I had to add gearing, which is challenging for two reasons: the tightness of the space, and because it is hard to mount stuff onto the motor in a solid way, so that the wheels don't fall off under extreme use. Furthermore, my first tests with 12:20 gearing (from the fast output) showed that it is just not enough; the Buwizz unit still kept shutting down, so I had to use 8:24, which is even more problematic due to the size of the 24T gear not fitting into a 3 stud space. After a lot of juggling with potential wheel hubs and connectors, I came up with this construction. The good part is that it does look like the leg of a bug :)

 

Front suspension

For the front suspension, I did not want to use a regular (5 stud tall) independent one, in order to have good ground clearance in the grass, and to make it look like a real beetle bug, which typically has a portal setup, with the lower A-arm raised, which again makes it look like a bug's leg. So I started experimenting if something like that could be done (using a wheel hub), and I managed to come up with the following solution. The trick here is that the lower arm's pivot is shifted (by preserving parallel movement), in order to be able to raise it. Furthermore, I used dual steering links, because the arms are 7L and the steering links are 6L, this way avoiding toe in/out, and having a tight steering response. Also, I incorporated the steering motor into the axle in order to be able to add a positive caster to the whole axle.

 

Chassis

The complete chassis looks like this. The front axle actually rests completely on the steering motor's face, form-locked onto it, while the motor is fixed to the rest of the chassis at an angle. The trailing arms are mounted onto a 3x19 frame, which forms the backbone of the chassis. I added a frame to the rear to imitate the shape of the abdomen of the bug, and to hold the Buwizz unit.

Exterior and interior

As for the exterior, I intended to use large panels and simple shapes to keep the weight down. The curved panels proved to be very useful; in combination with flex axles they form a nice roof / back that curves in two directions. Unfortunately, most panels (and the rim) are not available in many colors, so I decided to use a two-color scheme; black with an accent color. I experimented a lot with the colors digitally, and I basically liked two variants that were buildable: yellow and lime accents. And since I have virtually no lime inventory, I settled with yellow; I think it's an okay color for a bug. Furthermore, the lights are instrumental, both at the front and on the roof, to get a good bug-like looks :)

As for interior, I could squeeze in two reasonably sized seats, a steering wheel and middle console. I would have liked a different seat color, for example blue, but exactly the one 135 degree connector that would be required is not available. In blue. In 2025. No comment, Lego.

https://bricksafe.com/files/gyenesvi/vw-beetle-baja-bug/renders/Beetle Buggy 2.png/800x600.png

More pictures are available on Bricksafe.

Building instructions are available on Rebrickable.

 

About the race...

As I said, the race track contained wooden ramps for jumping. The previous year, we have examined the track, and it had ramps about 30 cm tall. Many of us were skeptical about the idea, and some builders made tests at home, and concluded that it seems quite impossible to build a buggy with two motors that has enough torque for the grass, but at the same time it is fast enough to jump from 30 cm ramps. Also, 30 cm seemed too much for lego creations. So we were expecting that the ramps would be lowered to about 10-15 cm. But no, the race was held on the 30 cm ramps. As a consequence, many models fell apart on the ramps, including mine, and could not finish the race (I believe two buggies finished, a super light one, and a fairly slow but stable one). The weak spot on mine was the front suspension. Due to the tricky portal arm build, it is not completely form-locked; the lower pin that goes into the wheel hub can detach under extreme stress of the 30 cm jumps. To be fair, I thought it would fall apart on the first jump, but it did hold out for quite a few, and jumped better than I expected (getting the model to go straight onto the ramps at high speed was quite a challenge though, even with this solid steering). Fortunately, the suspension never detached during filming the video, so it is strong enough for regular off-road terrain.

This year we will have the same race, but this time 4 motors are allowed for faster models (to be honest, I voted against it). I wonder how the race will turn out, those models are going to be quite a bit heavier as well, so I am expecting even more stuff breaking.. with higher speed comes the need for precise control as well, which Lego (and Buwizz) is not great at.

 

Let me know how you like it!

Cheers,

Viktor