Review - LEGO 42055 Bucket Wheel Excavator

The much anticipated (at least by me) set Bucket Wheel Excavator 42055. When this monster was announced, I knew I had to get him. Especially the new gear-part 24121 looks like a great addition to the Technic collection. I’m expecting a new wave of MOC from it. Let’s see if this set can meet up with the/my expectations.

To get an idea of scale of the build I’m accompanied by Tiny Toby and Tall Toby.

The box

The box is the biggest I’ve ever had (42009 and 42030 being the largest yet for me). It measures 57.8 x 47.8 x 16.8 cm and weighs 5970 gram. On the front the main model.

Behind the front are pictures of all the functions of the build.
At the back is the B-model, a mobile aggregate processing plant that separates large bricks/stones from smaller ones.
In the box we find another box, containing the bags numbered 1-3, bags numbered 4-8, an XL-motor, battery box and the instructions/stickers sealed in plastic.

In total there are 31 numbered bags.

The instructions consists of 1 large book, 1.9 cm thick and 541 pages long. The book is sturdy, and after the build it still holds together fine. This is the first time I see instructions numbered all the way through. Usually the steps-counter resets after a series of numbered bags is done, but this one counts all the way through ‘till 669. Also new for me was the white squares to indicated where a part needed to added when the pictures came crowded.

New parts

The inventory of 3927 parts can be found here.
First up is of course the 24121, the new quarter gear. It’s surprisingly sturdy and thick. There are 14 in this set, enough for 3.5 full circles

The other new part is the new Bucket 24120. I’m not sure why there is a new version of this, the old one could have been used too. A theory I found on Facebook is that the inserts inside the bucket makes the rocks fall out easier

Part 15458 is new in Dark Blue.

Another thing I noticed: All the 5- and 9-long axles are yellow. I assume that because they needed a few in yellow to do the railing, and they decided to make them all yellow. Makes the packaging easier.

The build – Step 1

Step 1 builds a little dump truck.It's about 95% the same as 42035 Mining Truck.

One bag in step contains only Light Bluish Grey and Dark Bluish Grey Cones and domes, representing rocks. It’s a nice touch, but somehow I feel like it’s an easy way to boost the part-count.

The build – Step 2

Step 2 builds the bottom part of the frame, on top of which the rest can rotate. I found this part a bit boring. Everything is double symmetrical, so often you have to build the same thing twice or four times.

The build – Step 3

Step 3 builds the 2 tracks on the side of the frame. It’s twice the same build.

The build – Step 4

Step 4 builds the structure that carries the 2 arms. During the build I wondered why there were Technic Wedge Belt Wheel (4185) sitting in different angles at the bottom. There were no belts in the inventory, so I was unclear of their use.

Turns out they roll on top of the large gearwheel to make the rotation more smooth.

In this part the first cluster of gears forms.

And the result after completing step 4. It’s starting to get big.

The build - Step 5

Step 5 makes the small conveyer belt leading to the dump truck

The build – Step 6

This is the biggest step in the build. I even had to presort the parts to be able to find everything. In this step the first half of the big arm is created, with the bucket wheel and conveyer belt.

the bucket wheel is put in quite tight. It takes a lot of pulling and pushing to get it in. Once in it’s held in place by 12 gears.

Something strange is happening in this part. To fully secure the connectors to the axle, the axle has to stick out a little, barely missing the other gear.

When completed you’re left with an impressively large piece. This is really a massive build.

The build -Step 7

Step 7 completes the large arm, adding the motor and a gearshift box to distribute all functions.

Not sure why these parts are used here instead of a standard connector. Or why one axle is red.

The driveline for driving, turning and the small conveyer belt are also connected with these parts. Here it’s more obvious. The parts don’t hold tight to the axle but can slide. This allowing some wiggleroom when lowering and raising the big arm.

The build – Step 8

Step 8 completes the model with the cabin, railing and other small stuff. The cabin is a little too small for a minifigure.

The end result


There are 4 main functions:

1. Powering the conveyer belt
2. Powering the tracks
3. Rotating the top. When rotating the top, the small conveyer belt turns with it. You can lock the conveyer belt so it stays in the same place, so the dump truck doesn’t have to move

4. Raising and lowering the bucket wheel. Unfortunately this is done by hand! In a set of 3927 parts I would have thought they could make this motorized?!


- Great parts pack. Almost all parts are standard parts that are great for rebrickable
- Relatively cheap (yes, I’m dutch). In this set the parts are about € 0.06 cent per part. In for example the Porsche this is € 0.12.
- Great new part: The big gear wheels. It’s going to make a lot of great MOCs
- The build itself is mostly entertaining. My build time was about 10 hours.

- Manually lowering the bucket wheel is cheap!
- Step 2 and 3 were kind of boring.

My conclusion is: Get this set! It’s a great model with lots of play features. And if you don’t like the model, you will get a lot of good rebrickable parts.

Thank you for reading. Any comments or questions are welcome in the comment section

Disclaimer: This LEGO set was provided for review by The LEGO Group. Anything said in this post is the opinion of the author and not The LEGO Group.

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