Technic

Cat D11 Bulldozer

A motorised Technic monster you drive from your phone, blade tilt and all.

4.4/5

Set 42131 · 2021

Pieces3,854

Minifigsn/a

Year2021

Set number42131

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The verdict

If you want a big, app-controlled Technic machine that actually shoves things around, this one gives you a proper engineering workout and a huge yellow centrepiece.

The tilting blade is a genuine first for official Technic dozers, and the finished model is gloriously oversized. Just go in knowing the Control+ app dependency and the steep price are the real sticking points. Grab it if you love motorised builds, skip it if you want manual functions or better value per motor.

Best for: adult Technic fans who love motorised construction machinery

The full review

What it is

Right, let's talk about the Cat D11 Bulldozer, because this LEGO® set is a proper unit. It's a licensed Technic recreation of the biggest, most powerful dozer in Caterpillar's real-world range, and LEGO leaned all the way in. You get 3,854 pieces, four motors, and the Control+ smart hub, which means once it's together you drive and steer straight from your phone, then raise, lower, and tilt the blade, work the rear ripper, and even fold down the access ladder. That tilting blade is worth pausing on. It's the first time an official Technic bulldozer has managed it, and reviewers were genuinely impressed that a mechanism this fiddly ended up with so little slop and backlash. The finished thing is enormous too, over 57cm long and 37cm wide, so it has real shelf presence and looks fantastic in that signature Cat yellow.

The catch

Now the honest part, because a mate wouldn't let you spend blind. The price is the elephant in the room. It launched at $499.99, and plenty of folks felt that was a lot to swallow, especially when the older 42100 Liebherr R 9800 excavator sits at a similar price with seven motors instead of four. The app dependency stings for some people as well. You can't play with any of the functions until the whole model is finished and the Control+ app runs its calibration, so there's no satisfying test-as-you-go along the way. And if the app then flags an error, good luck, because the gearing that usually causes trouble is buried deep inside where you basically can't reach it without major surgery. A few builders also just prefer manual Technic functions and find phone-only control a bit less tactile.

Who it's for

So who should actually get this one? If you love motorised Technic builds, enjoy the engineering puzzle of a big machine, and want a heavyweight display piece that drives around and shoves stuff, you'll have a great time with it. It sits comfortably around a 4.4 on Brickset, so the community clearly rates it despite the grumbles. If you're chasing maximum functions per dollar, or you want a set you can fiddle with manually as you build, you might be happier elsewhere. One more thing to know: it retired in December 2023, so it's aftermarket only now and prices have climbed well past retail. Go in with eyes open on cost, and it's a seriously fun beast to own.

The parts story

What the build is actually like, and the pieces worth knowing about.

Building this is a proper long-haul Technic session, and it's paced well. You start with the chassis and the drivetrain, laying in the motors and the Control+ hub, then work outward into the track frames and the big blade assembly up front. The blade linkage is the showpiece section, a genuinely clever bit of gearing that lifts and tilts, and getting it dialled in is the most satisfying part of the whole build. The rear ripper and the drive-and-steer setup keep things interesting, and most builders found it engaging rather than a slog, even at nearly 4,000 pieces. Fitting those tracks on at the end is oddly therapeutic.

On the parts front there's plenty for a fan to geek out over. The headline is a brand-new track link, the Technic Link Tread 7 with two pin holes in yellow, a wider 7-module tread with a chunky protruding cleat, fresh for October 2021 and tensionable on the model. You also get useful recolors: yellow 5x7 open-center beam frames, a stack of yellow 1x5 thin beams with axle holes (around 35 of them), a dark bluish gray gear rack housing, and six black linear actuators doing the heavy lifting on the functions. Add large yellow sprocket wheels and a 31x15 Technic wheel that hadn't appeared since 2015. It's a solid haul of practical Technic parts, even if the part-count value takes a hit from that premium electronics-and-motors price.

Fun facts

01The real Cat D11 is the largest and most powerful bulldozer in Caterpillar's lineup, so LEGO picked the genuine heavyweight to model.
02Tilting the blade is a first for any official Technic bulldozer, and reviewers were surprised how little backlash the mechanism had.
03The set introduced a brand-new wide track link (7 modules wide versus the old 5-module version from 2007), made from a softer plastic with a deeper traction cleat.
04It retired in December 2023 after just over two years on shelves, and sealed copies have since climbed to roughly $875, up about 75% from the $499.99 launch price.