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gyenesvi

[MOC] Jeep Bruiser Conversion (Manual & RC, 42110 + 42099 alternate)

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Hello Eurobrickers,

Finally I am ready to present my latest MOC, the so called Bruiser Conversion of the 4-door Jeep Wrangler. The real thing is done by JK Crew, it looks like this (more awesome pictures here):

jeep-bruiser-3.jpgjeep-bruiser-2.jpg

The conversion includes pimped up suspension, a longer body on the rear part, turned into a pickup, and larger wheels. As for the scale, the real Jeep Wrangler has around 80 cm wheels, and the conversion has around 110 cm wheels. I thought this would be an excellent material for an alternate build from the 42110 Land Rover set because of the color match and the available parts (like those rear mudguards), and the 80 mm wheels of the Defender, and the 107 mm Lego tractor tires result in a good 1:10 scale match. I thought it would deserve the large tires and a motorization, all available in the set 42099. So I ended up with two versions:

- Manual version, pure alternate build from 42110, with an optional raised geometry and large tires

- RC version that is a dual alternate with 42099

I will present both versions below. They are identical on the outside, they differ in the chassis build and the gearbox / drivetrain.

 

Manual version (42110 alternate)

I wanted to build something from the Land Rover that has a more aggressive suspension with large articulation. I have been playing with the idea of 4-link suspensions on both axles, and the 8 A-arms in the set are just enough for that. However, I had to do it with short springs only, so I used similar geometry as the rear axle of Grohl's stadium truck, but with longer lower links on both axles. Furthermore, I wanted to build it in a way that works both with the stock Defender wheels, and with larger ones. So I built a chassis in a way that the springs can be positioned in two places, and the suspension geometry becomes lower or higher. Along with this, the front axle is also moved one stud to the front, to make space for the steering of the front wheel (just like in the real version).

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As such a suspension requires a lot of space (if you want large articulation), the actual useful space in the middle of the model becomes relatively short. I wanted to preserve the same functions of the gearbox as in the Defender, so I had to compact it. Taking ideas from the Pimp my Land Rover project I managed to create a version of it that fits into the available space, keeping the same layout of the controls. Furthermore, I have included a functional V8 engine (the real one has a V8 Corvette engine).

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One part that I struggled with a lot was the HoG steering, as it was quite hard to bypass the gearbox and the front seats as well. Finally I managed to do it under the seats, but I could not fit a functional steering wheel as the chassis structure that holds the front suspension was just in the middle of its way. The interior came out quite clean and also replicates the real one quite well I think. The seats are similar to those of the Defender, but I had to make them shorter, as the roof is also shorter:

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On the outside one key point is that the real thing (at least this version) has its doors made of steel bars (which gives it a great look I think). This is good as the Defender would not have enough green panels to build 4 doors, but the bar doors could be built (at first I did not think I could get such a clean look, but I am quite happy with the result). On the front, I reused some ideas from my Willys Jeep, but changed it to a bit more modern look. On the rear part, the fender piece was an obvious fit, and I wanted to emphasize the bed with system parts, which also came out nicely I think. At first the A and B pillars and the roof was tricky to make solid, as it is only built from a few liftarms. But the final assembly is super strong, thanks to the column in the middle that goes through the gearbox (that was a key structural element to make). The model can be lifted safely with the roof. Some side panelling was also tricky to get into place, but I am satisfied with the overall looks. The doors, the hood and the tailgate are openable. The spare wheel fits nicely in the bed. One last feature I could add thanks to the Defender parts is the front bullbar with a compact functional winch (with rachet mechanism).

Here are some side-by-side images for a comparison. I think it works well with both wheel options.

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More info, pictures and building instructions are available on Rebrickable.

 

RC version (42110 + 42099 alternate)

For the RC version I decided to use components from set 42099 as it has everything required: XL motors for torque, heavy-duty CV joints, planetary hubs, more A-arms and hard springs for suspension and the few extra parts in black color. First of all, I wanted to motorize it in a way that I keep the interior and the functional fake engine as well. Second, I wanted to add a simplified gearbox. The placement of the battery was obvious in the bed, the steering motor would go onto the front axle, but the space required for the two (coupled) XL motors was less obvious. Finally, I could squeeze them under the rear seats, and place the gearbox in front of them into the drivetrain. As for the gearbox, incorporating a 2-speed one (hi/lo gear) was simple, but I wanted to do something more with the available parts. Finally, I managed to add an RWD/AWD switch. For this, gearbox routing is a bit tricky, going through itself through idler clutch gears, and returning later. Furthermore, the front and rear parts of the driveshaft rotate in opposing directions, which is resolved later by the proper placement of the differentials on the axles. It was really challenging to brace the whole gearbox properly so that the gears cannot skip anywhere, I had to rebuild and test it several times (those two coupled XLs have a lot of power). On the downside, I suspect the relative complexity of the gearbox add some friction to the system.

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As I wanted to maximize ground clearance, the front axle was tricky to build, since the planetary hubs can only be connected with ball joints when steered. For this, I applied the trick used by other as well, that slants the lower A-arms a bit, resulting in very slightly non-vertical front wheels, but it is so negligible I bet you'd never notice. The resulting axle is fairly slick, I am happy with the result.

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As the steering motor made the front axle higher, the functional piston engine had to be minimized as well, and I could only do a mini V6 with the available parts. Unfortunately, this small construction does not run super smooth in a V configuration (sometimes the 2L liftarms in the main shaft kind of collide into the half pins that make up the pistons for a moment, instead of smoothly pushing them up; the inline configuration with the same technique works smoother). For this reason, there is some friction resulting from driving the fake engine as well.

Here is the final chassis, and one more image about the ground clearance at the rear:

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Although the final gearbox construction is strong enough not to let the gears skip, there is one weak link: the driving ring can move out of the clutch gear under very high torque (although in my tests the model sooner went up the wall if not blocked). This is because the gear stick does not firmly hold it in place. However, it can be solved by fixing it into one position with a linkage coming out of the center column. This issue made me think how much more powerful it could be if the gearbox and the fake piston engine was bypassed, and eventually led to the construction of a heavy-duty variant (in which the gearbox is still kept, but instead controls the speed of the fake engine, when not in neutral). The heavy-duty variant is further geared down a bit to have even more torque. It can climb almost everything if the ground clearance permits, as you can see quite a few cases in the video.

A few more images about the whole model:

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More info, images and building instructions are available on Rebrickable.

 

Let me know how you like it!

Cheers,

Viktor

Edited by gyenesvi

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That looks like a nice, thorough alternate model! I like the way you built the sides of the bed with the wheel arches, like the real truck, but unlike most other real vehicles.

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17 hours ago, 2GodBDGlory said:

That looks like a nice, thorough alternate model! I like the way you built the sides of the bed with the wheel arches, like the real truck, but unlike most other real vehicles.

Thanks! Indeed, I like that part on the real truck, especially that the bed side goes well under the wheel arch on the outside, it's kind of unique, and I thought that's pretty easy to replicate with the existing parts.

9 hours ago, GerritvdG said:

Well done, really good looking model and also nice that it is buildable with limited parts. 

Thanks, I'm especially happy that I could do a fairly performing motorization without the need for custom electronics (as often is the case with large and heavy models).

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A lot of great work here - especially impressed with the gearbox  version. It’s far from easy to get decent off-road performance through a gearbox! Thanks for the detailed look at the design process. 

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On 9/16/2021 at 2:00 PM, Pattspatt said:

A lot of great work here - especially impressed with the gearbox  version. It’s far from easy to get decent off-road performance through a gearbox! Thanks for the detailed look at the design process. 

Thanks, I was also surprised how non-trivial the gearbox version is if you want to add more functions that a simple 2-speed one.

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