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Building the World’s First ONYX Mercedes G-Class 6×6 Part 1

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October 6, 2026

On September 3, 2026

At Kubay Design, we’re building what will become the world’s first ONYX-style Mercedes G-Class 6×6 — a project that pushes our engineering, craftsmanship, and carbon fiber expertise further than anything we’ve attempted before. The donor vehicle is a 2016 right-hand-drive Mercedes-Benz G-Class from the UK, already fitted with a full ONYX body kit. The brief is specific: after the 6×6 conversion, the car has to keep the recognizable look of its original ONYX tuning package.

That single requirement changes the entire approach. A standard 6×6 conversion uses body components designed around the dimensions of our own 6×6 platform. On this car, almost every one of those components has to be redesigned from scratch to work with the existing ONYX bodywork.

ONYX 6×6 Build: Key Facts at a Glance

Detail	Overview
Builder	Kubay Design
Base vehicle	2016 Mercedes-Benz G-Class (right-hand drive), ONYX body kit retained
Conversion type	Full 6×6 (genuine six-wheel-drive, not a visual kit)
Wheel & tire size	37-inch off-road tires on portal axles
Body approach	Custom carbon fiber arch extensions, designed and molded from scratch
Interior direction	Rebuilt in Mercedes-Benz G-Class W465 (2025) style
Signature detail	Lime green interior accent, carried through to wheel rim lips
Standout feature	First-of-its-kind ONYX-spec G-Class 6×6

A Truly One-of-a-Kind Build

This project stands apart from anything we’ve built before. Since most of the existing ONYX body panels were manufactured from fiberglass, our first step was a complete teardown of every exterior component to properly assess the true condition of the chassis underneath. With the vehicle nearing 10 years of age, imported from the UK as a right-hand-drive model, years of exposure to high humidity beneath the body kit had left considerable corrosion on the body.
Here’s what the first phase of the build involves:

Re-engineering of every body panel for the new 6×6 platform
Full teardown of all ONYX fiberglass body panels
Complete assessment of the chassis and body condition
Corrosion repair on all affected body sections
Full repaint of the vehicle

Cutting into the rear ONYX body panels to prepare the structure for the new 6x6 geometry.

-Engineering the Wheel Arches for a Wider Stance

One of the most demanding parts of this build is the complete redesign of the wheel arch extensions. A genuine 6×6 conversion requires portal axle gearboxes and 37-inch off-road tires, which dramatically widen the vehicle beyond what the standard ONYX arches were ever designed to cover.

Front Arches: Reshaped, Yet Faithful to ONYX

The front wheel arch extensions are being reworked and re-modeled from scratch, engineered to remain visually true to the original ONYX aesthetic while accommodating the new width. Custom carbon fiber overlays are being designed specifically for this purpose, keeping the signature ONYX silhouette intact.

Rear Arches: A Complete Structural Transformation

The rear arches demand even more extensive work. Our team is cutting into the existing arch structure entirely and re-modeling its shape to match the completely different geometry created by the 6×6 rear-end conversion. Each rear arch will also gain roughly 10 centimeters of carbon fiber widening — not just for correct proportions and a seamless fit with the rear bumper, but to ensure the wheels sit fully enclosed within the arches, meeting European regulatory requirements.

A Fully Functional 6×6 Drivetrain

This isn’t a cosmetic third axle — the technical side of the build is just as thorough as the bodywork. A through-axle drive system will be installed, giving the vehicle genuine, permanently functional 6×6 four-wheel-drive engineering across all six wheels. The factory transfer case, low-range gearing, and all original four-wheel-drive modes are being preserved and fully adapted to the new three-axle configuration.

The extended rear chassis with portal axle gearboxes, forming the structural core of the 6x6 drivetrain.

Standard vs. ONYX 6×6: How This Build Compares

Feature	Standard Kubay Design 6×6	ONYX 6×6 Build
Body components	Designed around Kubay Design’s own 6×6 platform dimensions	Redesigned from scratch to fit the existing ONYX bodywork
Wheel arches	Standard 6×6 arch extensions	Custom carbon fiber arches matching ONYX design language
Design process	Uses existing Kubay Design molds and parts	New design, 3D modeling and mold production from zero
Interior	Standard G-Class cabin, individually specced	Rebuilt in G-Class W465 (2025) style with sliding rear bench
Build timeline	≈ 2 working months (components in stock)	Considerably longer — custom design and fabrication required

A Complete Interior Transformation: G-Class 2025 Inspired

Perhaps the most striking part of this project is happening inside the cabin. The 2016 interior is being fully transformed into the styling and comfort standard of the new-generation Mercedes-Benz G-Class W465 (2025). Among the changes:

New steering wheel and dashboard
Front seats with massage, ventilation, and heating
Rear bench seat on custom sliding rails for extra legroom — a limousine-like effect
Reclining rear backrest with ventilation, heating, and additional airflow
Fully rebuilt headliner with a custom starlight ceiling effect

A Signature Color Story: Interior Meets Exterior

The interior’s primary color will be a vibrant lime green, an accent we’re carrying through to the exterior as well — the wheel rim lips will be finished in the same lime green tone, tying the entire build into one cohesive, unmistakable identity.

Watch the Build in Progress

Follow the build process on video — from teardown to the first test fit of the new arches.

Frequently Asked Questions

Is this the first ONYX-style G-Class ever converted to 6×6?

Yes — to our knowledge, this will be the world’s first ONYX body kit combined with a full 6×6 conversion, making it a genuinely unique build.

Will the 6×6 drivetrain be fully functional, or just for looks?

Fully functional. All six wheels receive power through a real through-axle drive system, with the factory transfer case and low-range gearing preserved and adapted to the new configuration.

Why did the arches need to be rebuilt instead of just widened?

The 37-inch tires and portal axle gearboxes required for a genuine 6×6 significantly widen the vehicle, so the original ONYX arches — designed for a standard 4×4 — had to be re-modeled, not just extended.

Can Kubay Design build a similar 6×6 conversion for my G-Class?

Yes. Every 6×6 project we build is tailored to the client’s specific body kit, interior preferences, and color scheme. Get in touch with our team to discuss your own build.