DavejspTechnicMOCs

<- Back to Index of Davejsp's Technic MOCs thread 42140 Racing Ripsaw Rebuild your "Transformation Vehicle" set 42140 into a remote-controlled "Racing Ripsaw"! About: This was actually my first alternate build for the 42140. The original model is already a kind of ripsaw, but I wanted to build a classic ripsaw, but styled for racing rather than utility, and pushed as far as the inventory would allow. My first instinct on gearing was to configure the set's gears for a 1:1.67 speed ratio, the same approach I used on the rally car, but thinking it through further, the tracks already carry a lot of inherent friction and drag from themselves so there would be a lot of wasted energy, and gearing down for torque would have made the model too slow for what I wanted. So I went gearless instead, a direct 1:1 ratio driving the larger rear sprocket wheels, which gives a better balance of speed and torque without the extra friction. I also made ground clearance a deliberate priority from the start, 4 studs is generous for this scale, and it's there specifically to give the model real off-road capability rather than just looking the part. I wanted to put the set's shock absorbers to use as well, so each track gets one at the front, with enough travel to keep the tracks properly tensioned without loosening up too much. The curved panels went into shaping an aerodynamic front nose, and the driver's cabin has a roof that opens to reach the hub's power button directly, which also made it easy to keep battery swapping accessible from underneath with no obstructions. At one point the build was largely finished but the rear end felt flat and visually boring, adding a non-functional V8-style block back there solved that; it doesn't do anything mechanically, but it completes the design and the whole model looks better with it in place. The rear spoiler wasn't part of the original plan either, I had some leftover parts and it just made sense to use them. Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com

Thanks! The 42037 didn't get much attention, maybe it's the color scheme putting people off, maybe it's something else, but I think it's underrated. The inventory has some really useful pieces for building car chassis, which made it a lot of fun to work with. Hopefully this quad bike alt build helps place more eyes on the set.

<- Back to Index of Davejsp's Technic MOCs thread 42037 Quad Bike Rebuild your Lego Technic "Formula Off-Roader" set 42037 into an Quad Bike alternative model. Background context: This set was another early purchase after coming out of my dark age, and the story behind acquiring it is almost identical to the 8048: spotted a used one going cheap online and bought it as a parts pack. What changed my plans was going to look for existing alternate builds afterward and finding almost nothing, like three MOCs for a set that's been out since 2015. So I thought, maybe I can contributte with something... Chapter 1: What to build? The first thing that pops up are the wheels, they're enormous, and they set the scale reference for everything else. With wheels that size, there aren't enough fairings in the set to build a fully covered vehicle, and going with a buggy or hot rod would have been too close to the original model's territory. At some point the idea clicked: a quad bike was a natural fit for both the parts and the color scheme, and that became the direction. Chapter 2: What functions to include? The Formula Off-Roader inventory has an interesting mix of pieces for its era. A functional fake engine connected to the rear wheels, rear axle suspension, independent front suspension, and steering all seemed achievable, it was then a matter of squeezing as much details as possible out of the available parts. Chapter 3: Fake engine block Both the original model and its B-model use an inline-4 style fake engine, but that makes no sense on a quad bike. I started with the idea of a 2-cylinder, but wanted to make proper use of all four pistons available, so I went with a V4. The set is missing certain pieces that would normally make a V-type engine straightforward to build, so getting the spacing and angles right took several attempts. The result is a compact V4 fake engine that works well within the constraints. Chapter 4: Rear axle and transmission Most quad bikes use a simple solid rear axle driven by a chain, but this set has no chain pieces. I could have kept things simple anyway, but I wanted to use the differential available in the inventory, which meant building a conventional transmission with a universal joint and a supporting frame to handle the differential and suspension properly. It looks unconventional, but it's there for sturdiness and functionality rather than aesthetics. Chapter 5: Front wheels, steering and suspension I wanted the entire front section, wheels, suspension, steering, to sit at an angle, which meant building it as a self-contained module and attaching it to the main chassis at that angle. The techniques themselves are standard, but the challenge was managing an increasingly depleted parts pool while trying to fit steering and independent suspension into very tight remaining space. It wasn't easy. Chapter 6: Bodywork The set has a reasonable number of fairings, but split across two contrasting colors. Rather than fight that, I leaned into it, one color at the front, another at the rear. The rear design came together quickly, but the front required several iterations before settling on a version I was happy enough with. Chapter 7: Details The set has no trans-red pieces, so the tail lights are represented using red pins and axles, a small creative workaround that reads well in context. The exhaust and muffler are built from pin connectors, and a few liftarms shape the fuel tank. The steering handlebar, headlights, and a bull bar round out the front end. The bull bar in particular went through several versions; by that stage the available connectors and axles were nearly exhausted, and I had to accept a solution I'm not entirely satisfied with rather than compromise the rest of the model. Sometimes that's how it goes. Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com

Hello, when possible, I would like to change my username from "BrisquesDesigns" to "DavejspTechnicMOCs" for consistency across different platforms. Thank you in advance.

Hello, when possible, I would liek to change my username to "BrisquesDesigns" as that's my new "brand" name on the internet, thank you in advance!

<- Back to Index of Davejsp's Technic MOCs thread 8048 RC Dune Buggy This MOC is a motorized alternative model for the 2010 LEGO® Technic Buggy (set 8048). It is built primarily using parts from the original set, with the addition of a few Power Functions components, to make this remote-controlled Dune Buggy Model. About: Much the same story as the 42095 Baja Racer MOC, still in the early phase of rebuilding my parts pool after the dark age, still finding new ideas in the sets I already owned. The 8048 is an inventory I kept returning to for the same reasons I've mentioned before: it sits at that interesting midpoint between the old skeletal studded style and the modern covered aesthetic, and it lends itself naturally to conventional RC vehicle designs. This Dune Buggy is another exploration of that, and a companion piece of sorts to the 8048 RC Roadster. It uses only the parts from the original set plus a few Power Functions components, which makes it one of the more accessible builds in this thread for anyone who already owns the 8048. The mechanical layout is straightforward: RWD through a solid rear axle at a 1:1 gear ratio driven by a single PF L-motor, front-wheel steering via a PF servo, and independent double wishbone front suspension. The 1:1 ratio keeps things simple and the lightweight build makes it responsive and fun to drive. Power button is easy to reach and batteries swap out quickly. Photos: Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com

<- Back to Index of Davejsp's Technic MOCs thread 42095 Baja Racer Rebuild your Lego Technic "Stunt Racer" set 42095 into an RC off-road Baja Racer/Trophy Truck alternative model. About: It was still early in my return to building, my parts pool was limited to the few sets I'd acquired since coming out of my dark age, and the 42095 kept offering up new possibilities every time I came back to it. I had several ideas floating around for that inventory, and this was one of them, a trophy truck style off-roader, another learning exercise in a sequence of builds that were each pushing my skills a little forward. The mechanical layout follows the same pattern as the 42095 Racing Buggy: RWD driven by one PF L-motor, auto-centering steering handled by a second PF L-motor, lightweight construction with a low parts count. Ground clearance is decent for off-roading, the power button is easy to reach, and batteries can be swapped with a quick partial disassembly. Simple and effective. What changed between the Racing Buggy and this one is mostly in the shaping, the Baja Racer has the proportions and stance of a trophy truck, which gave me a different set of visual problems to solve from the same bag of parts. Getting that silhouette right within the constraints of the 42095 inventory was the exercise, and it's one I enjoyed. Photos: Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com

<- Back to Index of Davejsp's Technic MOCs thread 42099 Sand Runner Rebuild your Lego Technic "4x4 X-treme Off-roader" set 42099 into an RC off-road buggy called "Sand Runner" alternative model. About: This was one of the first alternate builds I designed for the 42099, and it shows some of the characteristics you'd expect from an early exploration of an inventory, certain sections more refined than others and design decisions that taught me things I carried forward into later builds. The MOC looks good and performs desent, but it's also an honest snapshot of where my skills were at the time. The 42099 inventory includes four planetary wheel hubs with a 5:1 reduction ratio, a lot of torque, but at the cost of dramatically reduced speed. I chose to leave them out of the rear drivetrain entirely and instead run RWD through a differential with a final gear ratio of 2.34:1, which gives a much more satisfying balance of speed and pulling power. Remote-controlled drive and steering, independent suspension on all four wheels, and ground clearance of 4 studs at the front axle and 5 at the rear make it genuinely capable off-road. The hub power button is accessible from the driver's cabin, batteries swap from underneath without obstruction. The most valuable lesson this build taught me came from the transmission. The gear path I used involved more stages than necessary, and the consequences were immediate and instructive: friction, mechanical play, backlash, and lost performance at every unnecessary mesh point. Every RC car I've built since has had a leaner, more direct drivetrain as a result. Photos: Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com

<- Back to Index of Davejsp's Technic MOCs thread 42109 Le Mans Prototype Rebuild your Lego Technic "Top Gear Rally Car" set 42109 into an RC "Le Mans Prototype" alternative model. About: The 42109 is one of those sets that never quite found its audience. Most people who bought it did so for the Top Gear branding or to acquire specific parts from the inventory, not because the model itself was compelling. The original build was widely criticized for being slow and visually underwhelming, and the community reflected that: very few alternate builds ever came out of it. That's a gap worth filling, and this Le Mans Prototype is one of my first attempts at doing that. The goal was straightforward: build something that was faster, better looking, and more detailed than the original (like a modeled interior for example), and use the same parts to do it. The Le Mans Prototype format gave me a direction that suits the set's proportions well. It's RWD with a gear ratio of 1:3 a significant step up in speed from the stock build, with remote-controlled drive and steering. Batteries are swappable from underneath with no obstructions, this one needs a custom Powered Up app profile to run though, the setup steps are included in the building instructions, so it's a few minutes of configuration before your first drive rather than anything involved. I'm planning several more MOCs from this set. It's an underserved inventory that rewards the extra effort, and there's a satisfaction to building something genuinely better than what came in the box. Photos: Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com Feel free to share your opinion about this one!

<- Back to Index of Davejsp's Technic MOCs thread Power-Functions, remote-controlled Off-Road Racer MOC About: If you look at this MOC's parts, you'll recognize most of them from the 8048 Buggy I picked up earlier. That set has an inventory I kept coming back to, the proportions and the mix of elements lend themselves well to RC cars, and after building the 8048 RC Roadster MOC, I wanted to see how far I could push the same foundation with a handful of additional parts added to the pool. The result is a slightly more fleshed out build than that first attempt, with more refined shaping while keeping the same core functions. Both models share the same mechanical layout: RWD through a solid rear axle at a default 1:1.67 gear ratio driven by a single PF L-motor, front-wheel steering via a PF servo, and independent double wishbone front suspension. It handles off-road use well, and ground clearance is reasonable for the model's size. Battery swapping is straightforward with no disassembly needed. Where this MOC diverges from the Roadster is in how it looks. The styling was inspired by the cars from Rocket League, which gave me a clear visual direction to build toward and pushed me to think more carefully about the bodywork than I had on previous builds. It's still unmistakably a liftarm-based Technic model, but the shapes feel more considered, it's another step forward in learning how to make a better bodywork. Photos: Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com

<- Back to Index of Davejsp's Technic MOCs thread Power-Functions, remote-controlled small scale Dump Truck MOC About: One of the first sets I picked up after my dark age was the 42023 Construction Crew, I spotted a used one going cheap on a marketplace and saw it as a decent parts pack for having extra pieces around. It contains three smaller models, and the tiny blue dump truck among them caught my attention, mostly because it felt more unrefined then the others and left obvious room for improvement. My RC instincts kicked in shortly after and I thought that maybe I can redesign this truck and add remote control while I'm at it... That's the build. What makes it interesting as an engineering exercise is the scale. At just 27 cm long, 10 cm wide and 16 studs high, it's a compact model by any measure, and fitting a full RC system inside it, particularly a standard Power Functions battery box, which was all I had at the time, turned into a challenge. There was really only one place it could go: inside the dump bed, the wires then had to be routed and hidden through the chassis. The RC system uses a PF servo for steering and a PF L-motor driving two of the four rear wheels at a default gear ratio of 1.667:1 moderate speed with solid torque, and adjustable if you want to push it either direction. Despite the footprint, ground clearance is reasonable. The dump bed lifts manually via a side crank operating a small linear actuator that simulates a hydraulic piston, and the tailgate is secured with an axle acting as a hook that needs to be removed before it can swing open as the bed rises. The battery pack on/off button is accessible from the side of the dump bed without any disassembly. Like several of the earlier builds in this thread, this one doubled as a learning exercise, fitting a functional RC system into a constrained, small-scale model is exactly the kind of problem that sharpens your building instincts. Photos: Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com

<- Back to Index of Davejsp's Technic MOCs thread Power-Functions, remote-controlled Subtractor Racer MOC About: As the name suggests, this MOC is built around a subtractor mechanism. If you're unfamiliar with the concept, a quick online search will give you plenty of explanations and variations, but the core idea is that a subtractor allows a tracked vehicle to turn smoothly and be controlled just like a standard RC car: one input for forward and reverse, another for steering. It's an elegant solution to what is otherwise a clunky control problem with tracked vehicles. I came across the subtractor while browsing online for different mechanism configurations, I was in learning mode at the time, trying to understand what was out there and what could be replicated in LEGO. Something about it clicked immediately, and I wanted to build one. At that point my parts pool was essentially the 42095 Stunt Racer and a handful of extras, so that became the foundation. What followed was several days of iteration trying to arrive at a configuration compact enough to fit inside a small model, a subtractor takes up space, and making one that doesn't dominate the entire chassis is a genuine puzzle. Getting there was one of the more rewarding building experiences I'd had up to that point. It's worth noting that while many subtractor designs exist and are well documented, complete models that actually put one to use are surprisingly rare. This is my contribution to filling that gap. One L-motor handles propulsion while the second is dedicated entirely to steering, unlike traditional tracked vehicles where both motors drive the tracks and turning is achieved by varying their speeds. Because the steering motor contributes nothing to forward motion, I geared the drivetrain down to a 1.667:1 ratio to compensate with additional torque. The model is largely buildable from the 42095 set with some extra liftarms, gears, and miscellaneous elements on top. Control scheme: Photos: Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com

Thanks, it was indeed a challenge to add details because this set lacks parts for that purpose.

<- Back to Index of Davejsp's Technic MOCs thread 42140 Rally Car Rebuild your Lego Technic "Transformation Vehicle" set 42140 into a remote-controlled "Rally Car" alternative model and go tear those dirt roads! Features: Remote-controlled drive and steering RWD via solid rear axle, 1:1.67 gear ratio Ground clearance of 2 studs, suitable for light off-roading Hub power button accessible from the cabin Easy battery swap from underneath the car Requires a custom Powered Up app profile (configuration steps included in the instructions) The 42140 is essentially a ripsaw, a tracked, tank-like machine. Which is exactly why I wanted to go in the opposite direction with it. The whole point of an alternate build, to me, is giving someone a completely different play experience from the same bag of parts, and going from a tracked vehicle to a rally car is about as different as it gets from the same set. The parts inventory makes that kind of leap difficult. Tracked sets don't pack a lot of the elements that make conventional vehicle builds straightforward, panel fairings in particular are sparse, which meant the body had to be constructed almost entirely from liftarms. That constraint is what gives the car its boxy, angular look. That aesthetic is actually not far from how classic Technic sets were built, the structure visible in the shape. Given where I'm coming from as a builder, that felt right. I did push to include as much surface detail as the inventory allowed, so it doesn't look unfinished. Both rear wheels are driven by a solid axle at 1:1.67 ratio, which gives it enough pull for light off-roading at this scale. Ground clearance is 2 studs, modest, but appropriate given the proportions. One thing worth noting for anyone who builds this: it needs a custom profile in the Powered Up app rather than an existing one, so I've included detailed setup steps directly inside the building instructions. It's not complicated, just a few extra minutes before your first drive. Photos: Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com. Let me know your thoughts on this one!

<- Back to Index of Davejsp's Technic MOCs thread 8048 RC Roadster This MOC is a motorized alternative model for the 2010 LEGO® Technic Buggy (set 8048). It is built primarily using parts from the original set, with the addition of a few Power Functions components. About: The 8048 was the second set I picked up after coming out of my dark age, and finding it was one of those happy accidents that comes from browsing without any prior knowledge of what had been released over the years. I had no map of what LEGO Technic had produced during the twenty years I was away, I was discovering it all fresh, and when I came across this buggy I immediately fell for it. It's exactly the kind of build I gravitate toward: good looking, but with an exposed chassis where you can see the mechanisms doing their work. It also sits at an interesting point in Technic's history, right in the middle of the transition from the studded, skeletal models I grew up with toward the fully covered studless style that dominates today. It has one foot in each era, and that's a big part of why it appealed to me. Having just acquired the 42095 Stunt Racer and a few Power Functions components along with it, I was eager to try a motorized alternate build with this set. The result is this RC Roadster, and I'm genuinely happy with how it came together. It's RWD through a solid rear axle at a 1:1.67 gear ratio, driven by a single PF L-motor, with front-wheel steering handled by a PF servo and double wishbone independent front suspension. The build uses only parts from the 8048 set plus a handful of Power Functions components. It's lightweight with very little gear friction, honestly it runs fast enough that taking it indoors is probably a bad idea. The power button is easy to reach, and the IR receiver sits at the rear of the model for optimized signal reception. Photos: Full parts list, a video, and the PDF building instructions are available on my website davejsptechnicmocs.com