LEGO Technic 42131 Cat D11 Bulldozer [Review]

Like the latest ridiculously expensive smartphones, LEGO Technic flagship sets make you consider one question: is it worth upgrading? Same prices, same play features, and, maybe, a couple of new tricks to show off. This fall it’s all about the new LEGO Technic 42131 Cat D11 Bulldozer: 3,854 pieces, four motors, a bunch of new pieces, and a price tag of US $449.99 | CAN $549.99 | UK £419.99. Is the set worth upgrading from the reigning king 42100 Liebherr R 9800 Excavator? Let’s build and play with one and see what it has to offer.

The LEGO Group provided The Brothers Brick with a copy of this set for review. Providing TBB with products for review guarantees neither coverage nor positive reviews.

Unboxing the parts, instructions and sticker sheet

The new Cat D11 comes in a box that is the same size as the box for the 42100 Liebherr R 9800 Excavator, but unlike the excavator, the bulldozer got the new elegant black box targeted at adults. For some weird reason, the model indicated on the front is D11T, not just D11. Still, the official store lists the set as Cat D11. I wonder if any of the customers will ever notice whether they are assembling D11 or D11T.

More bizarre inconsistencies can be found on the back of the box. Somehow, the image of the box’s back listed on the product’s page reveals quite a different design. For instance, a callout with a close-up shot of “D11” marking is gone, not to confuse the customers anymore. I wish I could focus on the model instead, but you don’t see LEGO having troubles with the packaging design every day.

The inner packaging hides no surprises: a regular white box holds about half of all plastic bags with pieces. Upon unpacking, I immediately realized that there are only eight building stages, with most stages involving many parts. With the recent 18+ sets, I got used to each step is no more than one bag with 100-200 pieces, meaning no matter how long your work hours are, you can still find half an hour each night to spend with plastic bricks. For example, take a look at the 76391 Hogwarts Icons Collectors’ Edition: 22 bags for a slow and enjoyable build. I wonder if the Technic aspect of machinery models doesn’t allow for shorter building stages.

There are a lot of similarities between Cat D11 and Liebherr R 9800. Both models come with two volumes of building instructions. I wonder if designers considered alternative pictures for the books’ covers; the model looks cool, but a close-up shot of some part of the bulldozer may be nice.

While Liebherr R 9800 had no additional content included in the building guide, Cat D11 makes sure you know the real machine with six spreads.

Lastly, here’s the sticker sheet. There are only 15 stickers; many details are reproduced with actual pieces instead of printed patterns.

The parts

Whether you are a Technic fan or not, Cat will not disappoint you with the new pieces. First of all, it’s the new wider 7-stud-wide tracks.

Finally, Technic-builders are getting realistically-looking tracks; the new wider pieces have great proportions. And the yellow color is a bonus, too. Another great thing is that the new tracks are compatible with the old 5-stud-wide version. I’m not sure combining them in a bulldozer is a good idea, but it gives the potential for unusual builds.

It’s high time we got the wider version, as the rest are just too small for larger-scale models, especially those built with massive motors inside.

Linear actuators in black are the one thing I didn’t expect in the new Technic flagman set at all. Black is a universal color, and it’s fantastic to have such a specific element in color. I hope you agree the pieces would look better painted entirely black. Still, I wonder what the actual reasons behind the recolor are. I’m pretty sure the set won’t look awful with actuators in regular grey. And if you compare the model to the actual machine, you’ll notice some of the actuators are painted yellow.

The relatively new beams with alternating holes are yet another bonus of the set. In case you are looking for a good source of pieces, Cat is your choice. Just look at this pile!

There are other interesting pieces in the set as well. I suggest we take a closer look at them during the assembling.

The build

Right from the start, you are using two of the four motors coming in the set. Two angular motors drive the bulldozer. Initially developed for Mindstorms, these motors are perfect for precise positioning and provide a great play experience. I was also surprised to see the motors connected directly to the planetary hubs; no reduction, just pure torque. And a differential between the motors will help direct the drive to a fake V12 engine under the Cat’s hood.

The assembling is pretty straightforward at this stage, as the smart hub takes its place in the front part of the bulldozer.

The real fun begins at the next stage. Two medium motors come attached to a reasonably complicated gearbox. At this point, it becomes clear that not all functions can be activated at the same time. With two angular motors always driving the bulldozer and another motor switching the gears, there’s only one motor left to set a mechanism in motion. So, you won’t be able to lift the blade and activate the ladder simultaneously.

Next, two pre-assembled structures are connected. Although the build is far from completion, all the motors are in their places, suggesting no more major mechanisms follow.

LEGO has released a significant number of Technic trucks through recent years; building truck chassis has become pretty dull by now. But since Cat uses tracks, the build quickly becomes engaging at this stage. These are no ordinary track mechanisms: besides the gears of various diameters, you’ll find an extension rack that allows for tensioning the treads. The feature turned out to be extremely useful as it helps a lot with getting the treads on and off.

Connected to the body, the track wheels define the model’s maximum width, but the Cat is far from completion at this point.

Next comes the part that I didn’t expect to pay so much attention to. One of the extra play features of the set is a motorized ladder with an adjustable angle. It all starts with a neat combination of gears, including a white clutch gear; it is required to keep the gears safe once the ladder reaches either of the end positions — nothing extraordinary so far.

However, the next step blew my mind a bit. This build may look simple, but it takes advantage of the natural tolerances in the parts to hold the ladder at an odd angle. Add an angled gear, and you’ll get one of the most curious structures in a LEGO Technic set.

The cab turned out to be an impressive build, too. It is a separate unit that slips into place remarkably smoothly. And this is also one of those moments when you hope you won’t need to take the set apart in the nearest future.

Designers get bonus points for the structure’s rigidity. The dozer can be lifted with one hand using the roll cage over the cabin. This feels very sturdy and didn’t even hint at coming apart despite carrying it around a bit.

At this point, the only part lacking is the Cat’s blade. Unlike the Liebherr’s shovel, which came as a single piece, the Cat’s blade uses massive Technic panels.

And once the tracks are adjusted…

…Cat D11 is really to roll!

Playbility and functions

Since I saw the Control+ label on the box, I got myself ready that set will only work if I use my smartphone. Despite the system being around for a couple of years already, I simply can’t get behind it. The very thought that I will have to download something on my device, spend time pairing the hud and the app, updating software, calibrating the model, etc… it all makes the experience so much more tiring and tedious. I hate to start his part of the review with so many negative impressions, but this is how the set makes me feel.

The model is turned on and off via a red control lever inside the engine bay, which I think is pretty neat.

And I’m happy they didn’t reveal it on the box, as all the other features and functions are described there in detail, leaving nothing to be discovered later. Maybe it’s the concept’s flaw: a bulldozer isn’t the most exciting piece of machinery on the building site. The play features and the ways they work are extremely predictable, and this lowers the set’s value, in my opinion.

First of all, the dozer is slow. I expected the model to be slow when driving. However, the other motorized functions feel painfully slow. For reference, here are the timings:

  • The blade: from fully lowered to fully raised takes ~21 seconds (so 42+ for a full raise/lower cycle)
  • The blade: from fully tilted up to fully tilted down takes ~7 seconds (so 14+ for a full-tilt cycle)
  • The ripper: from fully raised to fully lowered takes ~8 seconds.

Secondly, half of the motorized features look questionable. For instance, the ripper is purely decorative, far from being even remotely useful. Do not get me wrong: I do not expect an 18+ LEGO Technic set to be actually capable of plowing, but it’s hard to ignore how enormously powerful the old 8275 Motorized Bulldozer was.

At least driving the dozer is fun. Powered Up motors are sufficiently powerful for heavy models, and the angular motors used in the drivetrain allow for very precise control. The app controls mimic the controls on a real dozer, but they’re not the most intuitive. That being said, they also don’t take too long to get used to, so it was pretty easy to make it drive and spin in circles, etc.

Speaking about the app, I won’t call the dozer section’s interface exciting or revolutionary. It’s exactly what you can expect.

Being too boring for kids and too safe for adults, the dozer is good for half an hour of active play. Next, it will most probably take its place on a bookshelf — if not in storage drawers. And before you think about placing it in your living room, take its size into account — the thing is massive.

Final thoughts and impressions

I wish I could call the new LEGO Technic 42131 Cat D11 Bulldozer controversial, but things are very apparent at this point. This ridiculously heavy (the box weighed 14.6 lbs), massive, and sulky model is nothing but an underwhelming LEGO product. And I’m very disappointed to declare that: the concept, the pieces, and the build are great. The set is full of brilliant moments, but the play feature, which is actually why the set costs so much, destroys the whole purpose of the product. I know that LEGO marketing and R&D understand what they do, and they won’t release an unsuccessful product, but I don’t see how it can be popular among LEGO Technic fans who know what they get for their money.

Every cloud, however, has a silver lining: for the same price, the 42100 Liebherr R 9800 Excavator is so much a better choice. It has seven motors (compared to only four here in Cat), and provides a lot more engaging play. So, I’m happy we don’t have to choose between the two machines. And if you already got yourself a Liebherr, there’s no need to upgrade.

LEGO Technic 42131 Cat D11 Bulldozer comes with 3,854 pieces and is available today for US $449.99 | CAN $549.99 | UK £419.99 as well as some third parties on Amazon, Bricklink and eBay.

The LEGO Group sent The Brothers Brick a copy of this set for review. Providing TBB with products for review guarantees neither coverage nor positive reviews.

6 comments on “LEGO Technic 42131 Cat D11 Bulldozer [Review]

  1. Jimmy

    I can pull out my lego from the 1970’s and get right to playing with it. I can pull out my old Power Functions stuff, add batteries, and get to playing. I can pull out my old R/C cars, throw in some fresh batteries, and get right to playing with them.

    But this? What am I supposed to do, keep an old cell phone around, hope it holds a charge and pairs with the device 25 years from now so that my bulldozer will work? No thank you.

    This is another example of Lego trying to make something work with some sort of app or cell phone and instead all it does is make sets needlessly complex and expensive.

    Usually I’d say I’m not the target market (Hidden Side, Vidiyo, etc.), but in this case these large Technic sets are right in my wheelhouse.

  2. Al Ex

    @Jimmy: it´s possible to control+ vehicles and builds in general directly with the powered up remote 88010. You don’t need any other device after the Hub Firmware setup. It’s possible with all of the powered up devices including control+. For everyone who hasn’t heard of it yet: it’s possible to upload small Python programs to the hubs. Then vou can run them locally without any other device after you uploaded them once.
    and Yes 100 years from now the CAT bulldozer will work with Lego 88010 remote

    Sources: Pybricks. Racingbrick, Technicmaster0 or only for CAT finished program: Eurobricks Forum „42131 – CAT D11 Bulldozer“ Page 46

  3. Russell

    I am surprised that nobody is pointing out that the final drive on the model is in the wrong spot – up on the top drive not the rear traditional drive position – its why Cat is Cat

  4. David Lee

    @ Al Ex. Unless i’m missing something, you still need a smart device for the initial set-up before using the new remote control, correct? On top of that, you need to upload a 3rd party program in order to use the remote control? If either of these 2 questions comes with a yes, then the toy by itself is incomplete coming out of the box compared to the previous power functions sets. This is probably the biggest grind most people have with Control+ when it comes to play ability. Any R/C toy should be self-contained and any additional features from an app should be an add-on, not the other way around.

  5. Gavin

    I have seen a number of people comment about the tracks. What this set finally brings is true bulldozer tracks. All the others to date have been excavator tracks. Have a look at real tracks for both. Excavators don’t have grousers (the cleats that stick out).

    One comment in the review about not being able to raise / lower the ladder at the same time as working the blade. This is true for the real machine as a safety system.

    However, being able to tilt the blade as well as raise / lower is a real machine function.

    The design team on this model had to work within some limits so this is a compromise. Personally I would like to have seen ripper tilt rather than the ladder, but that leaves this model open to modification which at the end of the day what lego is all about.

    the speeds are somewhat disappointing but again I think due to limitations of the motors and weights they have to move. This again is something that may be able to be modified.

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