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Hi, I think 42099 is a nice starter RC set of the PU line, so I set out to test what else can be brought out of all its parts. I'd like to share with you my set of 5 alternate builds from it. It has been a great exercise for experimenting with different options for suspensions, drivetrains and bodyworks, testing the versatility of this medium-sized set. In the end, all of the alternate models came out with quite different shapes, suspension techniques and motor/gearing setups, and I think I even managed to use those large turntables in some interesting ways. During my builds, I found that the set has a good array of structural elements, of course good drivetrain components, but is a bit limited on gears, axles and body panels. Nevertheless, once you get used to it, more configurations are possible than you would think :) Here are my builds in chronological order. Much more design details and images of each are accessible on the link behind each name. Here I shortly summarize the features and the differentiating factors of them.1) JeepyThis model was inspired by the release of the Jeep Wrangler set and its pendular suspension using the small turntables. - Pendular suspension using large turntables, both front and rear- 4WD slow drivetrain for good climbing, separate front and rear drive- Jeep-like exterior, focusing on the shape of the hood and the grill, plus the roll-cage 2) BuggyInspired by the release of the RC Buggy set, with this model the goal was to test how fast the the two XL motors can be geared up, along with creating a slick bodywork. - Independent long travel suspension with longer swing-arms both front and rear, high ground clearance- Fast up-geared rear wheel drive, independent for left and right wheel without differential- Positive caster angle at the front axle- Light-weight curvy bodywork, custom built seat 3) BeastyThis model aimed to test the possibility of building a live axle rear suspension using the large turntable, along with coupled motors for a stronger drivetrain. - Live axle rear suspension with push-rods for extreme articulation, independent front suspension- 4WD drivetrain with coupled motors driving both front and rear axles, adjustable gearing- Rough exterior, minimalistic interior 4) QuadroThe goal of this model was to build something other than a car, and to experiment with an unconventional motor setup. - Independent front suspension with positive caster angle, trailing arm rear suspension- V-engine built out of the joined drive motors, rear wheel drive- Functional steering rod- Chubby bulldog-like quad shape, bullbar 5) TrophyWith this model, I wanted to push the live axle possibilities further, creating long soft travel using only the short springs, and to find a sweet-spot in the up-gearing of the motors. At the same time aiming to create a larger-looking bodywork with the limited array of panels. - Long soft travel live axle rear suspension, independent front suspension- Rear wheel drive with motors built into the rear axle, independent left and right drivetrain without differential, faster gearing- Trophy-truck like exterior with curved front and long tail, imitated spare wheel All models can be controlled with the stock Control+ App, and the batteries can either be directly accessed from the bottom, or can be removed after detaching a few panels. All models are available separately or in a 5-in-1 pack on Rebrickable. I hope this makes you value your 42099 sets even more :) Let me know what you think!

Hi All, I'd like to introduce my alternate model for 42099. It was inspired by the recently released Jeep Wrangler, in that it has a small turntable based suspension on both wheels. Since 42099 has the two large turntables, I thought I'd try and build a similar suspension. Also, since it has yellow-ish parts, I thought I'd build a body with Jeep-like features. Of course, not enough yellow parts for a full body, so I focused on the front (hood and the grill to be somewhat Jeep-like) and used to rest to make a consistent body at least. Building instructions are available from Rebrickable: https://rebrickable.com/mocs/MOC-62435/gyenesvi/42099-c-model-jeepy Some details I have opted for a simple suspension design by moving the turntables as close to the two axles as possible. The drivetrain is also very simple, putting the drive immediately to the differentials, resulting in slow speed but high torque on the wheels. The left and right arms holding the wheels are fixed, the whole front and rear axles are rotating and are damped by the springs. Due to the large turntables, a single pivot point is enough to hold the axles at both ends. Naturally, the size of the turntables is a bit of a problem for ground clearance (about 3.5 studs in the front and 4 studs in the back), but not as much as I expected (see below).A major challenge was to mount the steering motor on the front axle in a small space under the hood and to create a strong enough steering rig using only one side on the front of the axle (as opposed to the two-sided rig in the original model). The next challenge was to create a chassis rigid enough to hold the end points of the springs in a small pivoting mount to enable the lengthening of one side when the other one shrinks. Naturally, the arched pieces available in the model are useful for this purpose, with further reinforcements later on. The battery is placed in the middle of the chassis, providing a low center of gravity with easy access to turn it on. It is not a structural part of the model, so it can be taken out easily after removing a few body panels. Also, there's plenty of empty space inside the chassis to hide the cables.On the outside, I wanted to replicate some Jeep-like features with the few available yellow-ish panels. I decided to focus on the front, creating an arched hood with a massive front grill and lights. I wanted a consistent yellow body, so I used all yellow pieces for doors and hoods, and none were left for a roof, so I decided to build just a frame. Luckily, the curved corner pieces and the long black axles available could be pieced together for a consistent frame, that matches the style of the front grill. I think the overall proportions of the model came out quite well. I was also able to include a quite clean interior. As for actual performance on real terrain, see the video for my own off-road tests. Surprisingly, the large turntables are less often a problem in terms of ground clearance as I expected. I suspect it might be because with the fixed-arm pendular suspension, as one wheel is lifted, it also lifts the turntable half-way, so it is less likely to hit something on the ground. Also, with locked differentials it can climb quite well. Be careful however, on real rocks, it is possible to scratch the bottom of it, including the motors.The model can be controlled with the Control+ App just like to original model. More pictures Let me know what you think! Cheers

REVIEW - 42099 - 4X4 X-TREME OFF-ROADER INTRODUCTION First of all, I like to thank the wonderful Eurobricks community for reinvigorating my interest in doing reviews. My motivation slowly dwindled up to a point where I considered quitting writing reviews altogether. But here we are again, with a lengthy review of the 4x4 X-Treme Off-Roader with the new PoweredUp elements and Control+ app. As a bonus I have added a section where I show you the unofficial B-Model made by @Didumos69. When it comes to PoweredUp/Control+ I am a bit late to the party, because upon opening the box, it was literally the first time I laid eyes on the new PoweredUp parts. I haven't had the chance to test or even see these new parts. Therefore, it's exciting for me to write this review and see what the fuss is all about. Of course, I have seen several video reviews, and some of them were very entertaining. RacingBrick made one of my favorites. I recommend checking it out. You can't go wrong with Sariel's review either, and his comparison with the 9398 - 4x4 Crawler from 2012. And if you haven't had enough of the videos, make sure to watch Zerobrick's review. Before we continue, I need to state that I like progress. I love new technologies. I'm not the kind of guy who wants to keep watching movies on VHS and rocking the good old TDK's. However, when a new technology emerges, most of the time, it's because the new technology offers a significant improvement over the soon-to-be-obsolete technology. In this case, the latter is the Power Functions system, first released in the 8275 - Motorized Bulldozer set from 2007. The main question of this review is whether the new PoweredUp/Control+ system is worth the money and offers a significant improvement over Power Functions. For this review, I used an iPhone 8 running iOS 13 something. PICTURES Pictures can be clicked to view hi-res versions. My Flickr album contains all the photos taken for this review. DISCLAIMER The CEE Team of TLG has provided this set. It's not my goal to promote this set. It's my goal to give you an honest opinion about it. Therefore, the opinion in this review is my own and is in no way linked to TLG. SET INFORMATION Number: 42099 Title: 4x4 X-Treme Off-Roader Theme: Technic Released: 2019 Part Count: 958 Box Dimensions: 52,8 cm x 48,0 cm x 12,4 cm Weight: 2156 gr Set Price (RRP): £ 199.99 / $ 249.99 / € 229,99 Price per Part: £ 0.209 / $ 0.261 / € 0.240 Links: Brickset, Bricklink THE BOX The limited part count results in the box being reasonably small. The bottom right corner of the box shows the new LEGO Technic Control+ logo and smart device. There is a message stating that a smart device is required, but I wonder if this message should have been somewhat more prominent. Or is it safe to assume that people scrutinize the box before forking out this amount of cash? On the other hand, people easily paying this amount of money will most likely have a smart device anyway. The back of the box shows the standard driving functions, together with a summary of what the Control+ app can do. Compared to the Land Rover, the box is quite a bit smaller. Yet the price is higher. Those PoweredUp parts don't come cheap. The Land Rover costs 180 euros, while the Off-Roader costs 230 euros, with a respective part count of 2573 and 958. For 50 euros less, you get around 1500 parts more, but you don't get the PoweredUp elements. Comparing these sets is comparing apples and oranges, so I'm not sure whether we need to draw conclusions based on this comparison. What I do find odd is that the Liebherr costs around 450 euros, but it does have 4108 parts and 7 PoweredUp motors and 2 Technic hubs. When you look at the price of the Off-Roader, it's safe to assume that the PoweredUp elements add around 100 euros. The Liebherr has over twice the PoweredUp elements, which results in approximately 200 euros of PoweredUp in that set. That almost makes up half of the set price. Even though the Liebherr is quite expensive, you do seem to get more value for money. CONTENTS OF THE BOX Opening the box and throwing the content on the table has seldom felt more underwhelming. Only six bags comprising the parts for this set, not counting the bag with rims. The box contains: 1x Instruction manual 1x Sticker sheet 4x Tire 1x Bag with 4 rims 6x Numbered bag with parts 1x Box with PoweredUp parts INSTRUCTION MANUAL RIMS Four commonly found rims. TIRES Four "Claas" tires to match the four rims, what a coincidence. This set is already the fifth set containing these tires. Your mileage may vary, but I am still deeply in love with these tires. TLG nailed this tire. Let's hope the rumored Mini Xerion will use a smaller version of this tire (edit: unfortunately, it does not). POWEREDUP The smaller inner box contains the Technic hub and motors. The box did take some damage in transit. This set contains the mandatory hub and three motors, one L and two XL. The two designations make you wonder whether we will get different versions in the future. Looking at the L motor, I can't imagine getting a smaller M version. It could be shorter than the L, but I don't see that happening. BAGS Six numbered bags and a bag with rims. HIGHLIGHTED PARTS This section describes interesting parts, and it won't come as a surprise that I will start with the PoweredUp parts. POWERED UP BLUETOOTH HUB According to Bricklink the name of the hub is Powered Up Bluetooth Hub, which confirms that this element is part of the Powered Up family. TLG calls it the "Bluetooth controlled smart hub". There's no denying that the hub is rather big. I have seen numerous complaints about the size, but the unit does pack the batteries, motor inputs and the electronics for extra functionality. The number of attachment points is limited, which might be more limiting than the size. Size: 9 x 9 x 5 XL MOTOR The XL Motor looks like a low-resolution pixelated version of the PF XL motor. If I recall correctly, lots of Technic fans were surprised by this sudden change in shape. I will discuss the form factor in more detail later in this review, but I can already reveal that I am a big fan, and that's an understatement. Comparing this XL motor with the PF version, the sheer number of attachment points is incredible. Size: 8 x 5 x 5 L MOTOR The L Motor is what it is. A motor with a slightly smaller footprint, but with less torque and a higher RPM. For more details about torque or RPM, I recommend visiting Philo's excellent page about LEGO motors. A limited number of pinholes, but enough to be able to mount it easily. Size: 8 x 3 x 3 (top and bottom are slightly larger than 3 units in the center) BRIGHT LIGHT ORANGE Out of the blue, TLG introduced a new shade of orange. And by out of the blue I mean that there is no obvious reason for this color, unlike the green variant for the Land Rover Defender. The only reason I can imagine is that regular yellow is too bright and orange is too....orange. I really like this new shade and I assume we will see more of it in the near future. Will this be the new dark azure? :wink: CONNECTOR BLOCK When we saw this new part most of us were convinced it was an April Fool's joke. It turned out to be a legit part. After that, I wondered whether we needed this part. Having used it a couple of times, this part is turning out to be one of my new favorites. CV JOINTS The new CV Joint Ball and CV Joint Axle are compatible with the new planetary gear hubs. I'm not sure whether these new designs will entirely replace the old CV Joint Axle and CV Joint, but I reckon they will be used in new heavier RC models. I' wonder if these will be used in the new Lamborghini, most likely with new hubs. PLANETARY GEAR HUBS The new Planetary Gear Hub is something AFOLs have been asking for, for quite some time. And TLG finally released them. They are not really suited for regular cars, but they are perfect for crawlers or heavy machinery. Here's a picture of the "complete assembly". WIRE CONNECTORS These new Wire Connectors are used to indicated which wire needs to be attached to a certain port on the hub. These little babies are nothing short of spectacular. So simple, yet so effective. I love 'em. TURNTABLES These turntables are definitely not new, but I felt like highlighting them anyway. This design is way better than the old one. COLORED PARTS If you don't need color in your life, or in the chassis for that matter, these are the parts you need to swap. Please, be aware that I missed a blue Pin with Pin Hole, so you need to swap four instead of three. And you need to swap the 3L Perpendicular Connector for a light bluish grey one. Not that's it is necessary, but if you want to get rid of the white parts too, these are the ones you need to replace. PART LIST A total of 958 parts. CONTROL+ Before I started the build, I tested the new PoweredUp elements. Please make sure to use six AA-batteries. It's quite easy to make the mistake of only using three batteries. You need to pull out the inner section so you can put in three batteries on the opposite side of the first three. Hook up the two XL motors to port A and B and attach the L motor to port C. Turn on the unit, fire up the Control+ app, and you are good to go. A simple wizard will take you through some simple introductory steps to get you started. Turning the Technic hub results in changing values in the corresponding tilt/pitch and roll meters. While there isn't much more to it (yet), it is a cool feature. The app also registers the "yaw" by the way. THE BUILD When I started the build, I planned on swapping the colored parts for black and grey elements. I even started the build with replacement parts. However, this being a review for an official set, it didn't feel right to start modding right away. Some members confirmed this, so I decided to start over, using the original parts. Since I already had built the front suspension, I can show you a comparison. In the left picture, you see the version with replaced parts. The right picture shows the original version. The picture below shows the front suspension with gray and black replacements. The original front suspension contains a lot more color. While some consider this color vomit, which it basically is, I do appreciate color in the chassis. It makes the chassis look less dull. That being said, I don't think that using orange was the right choice. Orange doesn't work well with bright light orange. Adding some more red, or blue for that matter, would have worked better in my opinion. TLG uses these orange 2L liftarms fairly regular, so it's not a big surprise though. This step ignited my love for the new motors. The new form factor of this motor is so much better than its Power Function counterpart. Not only does this version have more pinholes, but it can also be used to enhance structural integrity. The 5x5 total width and height and the 3x3 "protrusion" allow for perfect integration in a Technic chassis. With all the talk about the new PoweredUp parts, one would almost forget to mention another special part in this set, the new planetary hub. This new hub is roughly geared down 1:5. So for five rotations of the powering axle, the wheel will do a single full rotation. It's very cool that TLG is actually releasing these kinds of parts. It shows that they are constantly improving and maturing the Technic product line. The smaller of the two motors can also be mounted perfectly, even in smaller cars. These new motors are shaped to perfection. It almost makes you wonder why TLG chose round ones when they released the Power Functions system. Attaching the two sub-assemblies results in the, more or less, completed front suspension. The two motors fit in nicely and they both add rigidity to the model. The shape of the chassis doesn't need alteration to accommodate the motors. The big turntable mounted at the front allows the front suspension to rotate freely. The bodywork will be attached at a later stage. The rear suspension doesn't have steering, so it's built differently. This sub-assembly doesn't contain as much color as the front one, but you can still see some yellow and orange. The other XL-motor is mounted the same way as in the front suspension. Due to the lack of steering, there's no L-motor and the rear suspension is a bit shorter than the front one. The turntable is placed inside, instead of outside. The chassis is almost complete after combining the front and rear suspension. And yes, I forgot to mount the shock absorbers. I was too busy with routing the wires that I didn't even notice this when I took the picture. The smart hub is mounted behind the seats. The wire connectors are a welcome addition. Not only do they provide a way to attach the wires to the chassis, but the color-coding allows for easy identification. Job well done! Building the chassis was fun and the final assembly feels rigid enough to take some beating. It's hard to resist mounting the wheels before the end of the build, so that's what I did. Eager to try out the new Control+ app, I turned on the smart hub and everything worked smoothly. The suspension test also turned out the be successful. Even though the same shock absorbers are used, the front suspension feels less stiff than the rear one. Time to build the bodywork. Aaaaaand it's done! Usually, I always apply the stickers when I review a set. This time I decided to omit the stickers to see how the model looks. And you know what, it looks awesome. The bodywork looks phenomenal and doesn't need stickers at all. Being able to easily attach and detach the bodywork is a big plus. If you don't like it, it's very easy to create your own version. Or the same body, using a different color, which I will show you in a bit. The on/off button can easily be reached and the wires are routed nicely behind the liftarms. Maybe I missed two black pins, but these look like the usual leftover parts. COMPLETED MODEL I absolutely love the though look of this crawler and I like the fact that this model doesn't need stickers for its appeal. I have said it before, but TLG hit it out of the park when they designed these tires. Various bars protect the car from being damaged when it rolls over. The bed of the crawler has ample space to place the battery box. It's very easy to replace the batteries. The front and rear view don't look particularly appealing, but being a crawler, that's what you expect. Another front view pic from a different angle. And a rear view one. The bottom view shows the suspension and motor placement. ALTERNATE BODYWORK Since it's very easy to swap the bodywork, I decided to create a white-and-black version. The original colors works very well for me, but this combination isn't too shabby either. Maybe we can reinvigorate the Eurobricks Car Chassis project and design some cool detacheable bodyworks like this one. Here are some pictures with the white body attached to the chassis. POWEREDUP/CONTROL+ VS POWER FUNCTIONS The main question we need to address is the new PoweredUp system. How does the new kid on the block stand up to good old Power Functions. HUB The hub is rather bulky, but it does include all the batteries. Since PoweredUp isn't using IR to communicate, you can place the hub somewhere in the chassis. Of course, you do need to think about an option to detach the hub from the chassis to replace the batteries. Unfortunately, the Technic hub still uses batteries, instead of an internal rechargeable battery. For all my EV3 units I purchased the rechargeable battery, which makes it very convenient to simply plug in a USB cable and charge the unit. I sure hope TLG will provide options for this in the future. Of course there are (and will be more) third party solutions, but I'm talking about a solution for the purists. MOTORS I cannot express enough love for the form factor of the motors. I highly doubt TLG will ever top this design (we will read this statement in ten years and laugh out loud). Using the motors to provide extra structural rigidity is very convenient. And the motors do nicely fit in a 5x5 chassis assembly. I was hoping for a bit more torque and speed. In other words; I was hoping that PoweredUp would bring a significant performance upgrade compared to PF, but unfortunately that is not the case. CONNECTIVITY Using Bluetooth over Infrared does provide a wider range of options. And it's less prone to communication issues (like IR has in the sun). That feels like a step forward. "But what happens when TLG doesn't support the apps anymore?" and "I don't like to give my kids a smart device to control LEGO sets. Can't I use a regular remote?" These are very valid questions. I am not opposed to using a smart phone to control these vehicles, but I would love to be able to choose between a smart phone and a regular remote, like the PF one. Hopefully TLG will provide better support for physical remotes, like the one used in the new train sets. And for TLG not supporting the apps anymore; by the time TLG drops support for the Control+ app there will be loads of third party alternatives. Therefore, I am not afraid that we can't use PoweredUp anymore in a decade or two. MOCs For now, I do think that PoweredUp and the Control+ app lack in one department and that's the MOC-ing department. When you design your own creation, you aren't very flexible when it comes to controlling the model. You basically need to use an existing profile in the app. I started creating a PoweredUp chassis for the 42039 and I soon found out that one of my motors needed to turn counter-clock-wise. There is no way I can change this in the app. This will hopefully change in the future, when TLG releases an SBrick like profile creator. But for now, I consider this a major downside! BRICKCONTROLLER2 Lucky for us, there will always be people like @imurvai who invest their time to create cool project like BrickController2, which allows you to control all kinds of LEGO hubs, and thus motors. Check out this informative video made by @kbalage aka RacingBrick. All in all I am very happy with PoweredUp and I am looking forward to what the future will bring, but I do need to address that Power Functions still offers more usability and flexibility at the moment. B-MODEL - ROCKY Remember the good old days when TLG designed B-models to provide some added value. Those days have been few an far between. Again, lucky for us, we do have an awesome community with awesome members. In this case Eurobricks member @Didumos69 created a remarkable B-model, which I will be reviewing as well. Thanks to Diederik for providing me with instructions. In case you like to build it yourself, the instructions can be found on Rebrickable. We even have a dedicated topic if you like to discuss this model. As usual, I had my lovely wife Kitty disassemble the A-model. She knows I hate, or rather not like, disassembling models. Thanks babe! You start by building the middle section, which is kind of the pivot point of the model. The basic setup is more or less the same as the original crawler, which is not surprising at all. The front suspension contains the L and XL motor, for steering and driving. The front wheels don't have independent suspension. Instead, the entire front carriage is suspended. Since the front suspension is attached to the turntable, it is able to rotate as well. The rear suspension is also attached to a turntable, but it only has a single motor, since the rear wheels don't steer. The picture below shows the finished chassis. The smart hub slides into the middle section, where the wires are attached. The color coded wire clips are well thought out and they are properly used in this model as well. Due to the limited availability of certain parts, some very minor concessions have been made. But overall, it's a great build and a great chassis! The bodywork is very limited, but this B-model is not about the bodywork. It's about performance of the chassis. That being said, the bodywork has been designed elegantly. Both sides are detachable to access the battery box. Detaching, and especially attaching, the sides is somewhat cumbersome because there a lot of pins which need to be attached at the same time. But practice makes perfect so it gets easier over time. The collection of leftover parts. This model definitely looks like a proper B-model. Without the limited part restriction, this could easily be turned into an A-model. As it is, it's somewhere in the middle between an A-model and a B-model. Please bear in mind that I am talking about the looks, not the performance. It's worth mentioning that when you test the suspension, the axles going into the motors will slightly rotate. This results in the model not fully returning to its original position. When you drive the car this will automatically be corrected to return to 40% compression again. The side view shows what a proper crawler looks like, lean and mean! TLG has released several 4x4 off roaders. None of them are officially called crawlers, because they aren't actually crawlers. This is one of the best renditions made with parts from an official set. Like the A-model I won't be providing a video of the B-model. I can recommend watching two cool videos, one by Diederik himself and one by RacingBrick. Of course, I did test the performance of this model. It's impressive to say the least. It could actually drive up the back of my couch, before it fell over hehe. I definitely recommend getting the instructions and build this B-model. You will have tons of fun with it. Probably more than with the official model SUMMARY I am glad to see TLG constantly improving and maturing the Technic product line. The popularity of SBrick and Buwizz made going down the smart hub road a no-brainer. And I am glad the TLG thinks the same way, and that they are not ignoring RC products. However, I do hope that we will still get big models with manual controls instead of an elaborate line of PoweredUp/Control+ sets. Hopefully, TLG will find the right balance to keep pleasing AFOLs as well. PoweredUp needs to mature before being able to fully compete with third party controllers. The lack of custom profile creation is a major drawback. Comparing PoweredUp with Power Functions, the form factor of the new motors is stellar, but the lack of custom profiles makes it very hard to use PoweredUp in a MOC. And the need for a smart device is limiting as well. PoweredUp is a very cool product line and I am looking forward to what the future brings, but at the moment Power Functions are more versatile. Overall I like this set, but I do think it's better to fork out some extra cash and get the Liebherr. PROS Cool design, even without stickers Body can be easily attached and detached PoweredUp motor form factor is out of this world Wire connectors are spot on New bright light orange New planetary hubs (and new CV Joints) CONS Performance is so so PoweredUp performance isn't significantly better than PF No custom profiles for Technic hub No additional features, besides its off-road capabilities No official B-model Value for money feels off SCORE SCORE How do I rate this set? 9 DESIGN Cool design, even without stickers. 7 BUILDING EXPERIENCE Decent build, but no gearbox or other Technic assemblies. 7 FEATURES No additional features, besides its (limited) off-road capabilities. 7 PLAYABILITY Can be fun when creating an off-road track. 7 PARTS New bright light orange parts, CV joints, hubs and PoweredUp elements. 6 VALUE FOR MONEY The value for money feels off, compared to the Liebherr 7,2 HOPED FOR BETTER PERFORMANCE

Hi To whom it may concern. My one month old 4x4 extreme 42099 lost power at the rear wheels. I then took it apart to see if something might be stuck in the gears etc. No, everything mechanical including hubs were fine. Ran the rear powered up XL motor outside the truck and found that it made a grinding noise vibrating excessively and started to sieze when rotating anti-clockwise (truck moves forward) , but reverse works fine. What to do? Is there such an replacement motor available? Think the motor overheated because of resistance when not being able to make a climb etc. overload. Or just a bad motor? Why does the motor vibrate excessively and struggle to rotate ONLY anti-clockwise? Have anyone had this issue? Please advice.

Rocky - 4WD Rock crawler buggy I would like to present to you 'Rocky', a rock crawler buggy with a body tilting angle that averages the angles made by the front and rear axles. My shot at a 42099 B-model. Instructions are available on Rebrickable. When I saw the first images of 42099, I noticed that the amount the body tilts sideways, is mostly defined by the rear axles angle, because that axle's suspension is the hardest - it carries the battery/control unit - and it's not pendular. That got me thinking; wouldn't it be nice to make a setup in which the body tilting angle averages the angles made by the front and rear axles? Just like how a Mars Rover averages it's body angle between it's rocker bogies - with a differential - but now sideways, not lengthwise. That way it should be possible to mimic the character of 4-link suspension, which is often seen in rock crawlers. So that was my objective with this B-model and the nice thing is that this model contains exactly the parts needed to build something like that. Axle articulation Here is the setup that interconnects front and rear axles. Like in rocker bogie suspension, you should regard the body as the differential house. The body tilting angle is defined by the two axles that point sideways. I used 4 gears in the differential itself to minimize slack in the system. There is some rotational slack of course, but this is even further reduced by 1:3 given the 20:60 gear ratio with the turntables. Center of gravity Besides the differential, the center module also houses the battery/control unit, because that unit includes the tilting sensor and I wanted the tilting sensor to show the tilting angle of the body. I also wanted to keep the center of gravity low and centered. However, putting the unit in this central spot did cause issues later on... The battery/control unit - not depicted here - plays an essential role in form-locking the whole center module. The battery/control unit can be slided out sideways after removing a few pins and parts. Spring suspension Besides axle articulation, I of course also wanted to include actual spring suspension, so I attached two main suspension arms to the turntables, one for the front axles and one for the rear axles. I suspended the main suspension arms with springs placed between the turntables and suspension arms. The springs are mounted differently to the front and rear suspension arms, giving the car a little more lift in the back, which adds to a nice inclination, or rake angle, of the whole model. The whole model nicely sinks into the spring suspension under its own weight up to about 40% percent of the overall spring travel. Drivetrain I wanted to have the most simple drive train possible, so the motors are directly attached to the frames holding the differentials. This is a crawler and with the new portal hubs, there is no need for any up or down gearing. The motors add to the stiffness of the main suspension arms. I also wanted to have a track width that is two studs wider than the stock 42099 build. After some playing around I found out I could use the new CV-joints the other way around to make that possible. Steering For steering I wanted minimal slack and double sided steering rods like in the stock 42099. I limited the steering angle to make sure the maximum angle the CV-joints make, does not cause any damage. I noticed the CV-joints start wobbling when the angle they make is too big. The steering rack assembly - as well as its back side counterpart - use a trick to minimize unintended movement (slack): The assemblies are 3 studs deep and incorporate 3L axles with end-stop. The end-stops are sticking out of the assemblies and make them slightly deeper than 3 studs. For this to work the end-stops need to slide along a smooth surface. This trick makes for a very nice fit with little play and still allows the assemblies to move very smoothly. Ground clearance To increase ground clearance I used a double wishbone setup, not suspended, to take advantage of the extra lift provided by the inclined wishbones. The rear wishbones are inclined more than the front wishbones, because there the CV-joints don't need to deal with the steering angle. At this stage I also added a set of minimalistic fenders ;-). Bodywork Finally, bodywork. This was the most challenging part for me. It needed to be removable, to provide access to the battery/control unit and I wanted it to live up to my foolproof standards. The whole model can be lifted by the roof or by the A(?)-pillars. At this stage I practically used all the pins that came with the set, so I had to do a lot of backtracking to get some pins available. I ended up using all pins, including the ones that came as spare parts. Interior RC don't have interior . When I wanted to test drive with a first bodywork attempt, I found out the hard way that I could not reach the on/off button of the battery/control unit. I had not taken that into account. Eventually I found a solution in making the roof openable, as if it were a hood, just by releasing two pins. The red 10L axle in the back can then be used to turn the controller on. After opening the roof, it can be removed easily, after which the sides of the body can be removed separately to access the battery/control unit. All together this has been a great experience. Especially the limited and pre-defined set of parts made it a real challenge. It forced me to revisit all constructions over and over again, and leave in only what is essential, without making concessions to my self-imposed building standards. I ended up using 828 of the 958 parts.

Hi All! Since last tuesday I own all new sets and I've recorded many videos (speedbuild, functionality reviews, detail views...). Thank you for watching! 42099 4x4 X-treme Off-roader Functionality review: https://www.youtube.com/watch?v=6ZfIpFKcUME Speed-build: http://youtube.com/watch?v=jgss_ZFzWEA First Look at App release: https://www.youtube.com/watch?v=pIb-Al_3o5g Control+ packiging: https://www.youtube.com/watch?v=oas_z6tcJA0 42098 Car Transporter Functionality review: https://www.youtube.com/watch?v=sHOuPBHtDtg Speed-build: https://www.youtube.com/watch?v=kY9N-2lezZI 42097 Compact Crawler Crane Functionality review: https://www.youtube.com/watch?v=Z4oRcbnZMBU Speed-build: https://www.youtube.com/watch?v=bvelE1MXuaA

My own speed build video of LEGO Technic 42099 4x4 X-treme Off-Roader. Funcionality review video will be later in august. Currently the control+ app is not available for download :D Speed-build video: https://www.youtube.com/watch?v=jgss_ZFzWEA