Zerobricks

Here's a IRL build of the rear axle: I made my own planetary hubs using the new pieces and old turntable:

Thanks to the new photos, I could make a rough estimation of the rear axle: It seems the drive from XL motor is geared up two times using 20 and 12 tooth gears before going into the differential, which is very odd.

Okay, here's what I can see from the analysis of the new photos. The hubs also have a crosshole behind the normal pinhole so you can mount stuff. There is also something red inside them, I assume it's the female CV joint receptacle. The CV joints seem to allow some axial movement in order to compensate for uneven joint and suspension arm length in the back. The front suspension pendular axle assembly goes all the way to the back axle, you can see another large tuntable right behind the rear axle. The battery box is placed in the back and not in the middle as expected. You can see the new 3x3 biscuit piece first found in Spike used in the rear and probably the front. The rear hubs are reinforced with 6L links in order to prevent wobbling. Interesting enough, designer used friction 3L pins where suspension arm meets the body, but not where arms are attached to the hubs.

The hub has internal tilt/accelometer sensors, you can see the graphics showocasing that. Also the new PU motors have step counters in the back of the actual motor, so they can control many RPMs they spin.

You mixed up studs with centimeters 33cm is around 41 studs.

It's some 30 studs wide, which is some 3 studs wider than 9398. It's also very short, only 33cm cong.

Found another photo, showing more detailed view of the model: You can clearly see dimensions and the side of the model. Source: https://storgram.com/post/ByPBQFzJ9ar

Because it's fun to see how things are made? Also a day before pictures of 42099 popped up, I posted my creation:

You could use the gearbox changeover arm to push the balls up the ramp and still have it freely fall down on the axle.

I decided to wait for more photos to pop up before continuing on the replica.

I think the only functions are driving, steering, suspension and ability to remove the bodywork to acces battery box.

Can't place XL motor in L's place, because than the gears are out of system... Unless they used 3x20z tooth gears?

Yes, right, my mistake. You can see the motor's orientation in the photo.

Than you for the praise. I hope to improve the model with the use of the new hubs and joints, and no longer requiring use of bevel gears.

Took @efferman's advice and moved the L motor a stud higher and improvised a bit: I used the new connectors from Spike where I thought they may be useful I used the same centering mechanism for front steering ZEUX uses: How the replica currently looks: I think from this point on there will be more or less just improvization and I think I can start IRL building.

Decided to try to build a replica of 42099, first staring in LDD: Here's where I found a problem,: I can't decide if the motor inside the axle is the L motor for steering, or the XL for driving: Judging by the circled axle, it seems like a 4 tan axle with stop for driving the differential inside the H frame: But if there is indeed an XL motor inside the front axle, than that leaves no space between the bottom of the XL motor and the differential to reute the steering axle: And same issue if the L motor is steering, there is no space for drive axle to pass under it: Any ideas, guys? Some reference photos of the motors (stolen from RacingBrick ):

They DO have gear reduction inside, they are planatery hubs, and they are 1 stud wider than normal ones to accomodate the additional gears.

I think I figured out how the hubs are designed!!! The ball joints are FIXED to the hub in order to accommodate the new larger CV/Cardan joint. In order to use the hub for rear suspension you simply rotate it 90 degrees so what were the steering arms before hold the weight. Also, I'm working on a replica

After completion and playing with the Leopard for a few months, I noticed the model had a few shortcomings which I wanted to eliminate with this version. These include: Suspension oscilations at high torque High center of gravity Instability on rough terrain at high speeds Most of these issues were due to the usage of the torque tube suspension which is simply too heavy and unresponsive at high speeds. What I needed was to replace the live axle suspension with independent suspension while keeping the articulation needed for offroading. Here's what I came up with: Let's break down the suspension to it's basic components to better understand how it works: Colored green are the main shock absorbers. These caryy most of the wight and provide a high suspension travel Colored orange are the gearbox transfer arms which fix each perpendicular gearbox firmly to the suspension, thereby reducing friction and fixing the U joints to keep them from popping out. Colored black are the side beams which help guide the transfer arms and hold the suspension together Colored in red and gray are the two independent drivelines powering the wheels. Finally in transparent, the suspension arms are made as long as possible for maximum suspension travel. I built the first version with this setup, but soon discovred a flaw. The torque from the drivelines would push the suspension arms down, causing the suspension to stop responding (indicated with red and grey arrows in photo above). In order to solve this problem I added the suspension bridge above, colored in pruple. The suspension bridge performs the following functions: Compensation of the driveline torque Supports 20% of the model's weight Improves articulation when going over rough terrain With the suspension solved, I turned my attention to the chassis. I wanted a model with high torque and high speed. To achieve that I installed a two speed gearbox for each independent driveline powered by a total of 4 RC motors: Finally a very sturdy chassis based on frames was built to support the model. Each axle was given it's own independent steering with servo motor and each driveline has an M motor for switching gears. This redundacy means that even if half of the model breaks down, it can still drive back home. Next step was building the model in real life. Thanks to ForwART's custom stickers the exterrior really came to life: The doors can be opened, revelaing two seats and the steering wheel: Each wheel has over 6 cm of wheel travel, allowing the Tiger extreme articulation rivaling live axle setups: And let's not forget the most important photo of them all: Finally, since there is only so much I can tell in words, enjoy the video experience: As usual the LDD file of the model is available by clicking the photo or link below: https://www.bricksafe.com/files/Zblj/tiger-4x4x4/Tiger 4x4x4.lxf To summarize, compared to the previous Leopard, the Tiger has the following improvements: Improved stability due to the independent suspension and low chassis Higher top speed due to the gearboxes Eliminated suspension oscilation Improved performance at high speed thanks to lighter and more responsive independent suspension Improved maneuverability thanks to all wheel steering Sadly there are also a few drawbacks which I plan to fix in the future version: When pushing the model hard in Ludicrous mode and in low gear the 12 tooth bewel gears can get damaged and need to be replaced Low steering angle (18 degrees) Because only one servo motor is used per axle, steering is more prone to be bumped out of center.

Great progress Grum. I would just give a small recommendation to improve the mod of the set. Put some kind of a stop on the 3L axle with stop inside the portal hub, to keep it from sliding out of the 8 tooth gear and the universal joint, something simillar like 9398, 42030 or 42070 have.

I am talking about what 8 springs can support, either of these combinations or something in between. For example Chiron uses also 8 springs, to support some 3,5kg with 1 stud of suspension travel.

Bigger wheels and tyres would explain why Lego developed new, stronger hubs and CV joints.

What about using train motors?

Lots of good details and functions, clever drive sytsem but I think you can do better. No suspension, and no portal or planetary hubs?

Thank to everyone for the feedback. When I have some spare time, I will update the bible with articulated steering, correct the Tatra camber angle mistake and add suggestions by Sariel.