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Rivian’s Enduro drive unit marks a turning point in the company’s approach to electric vehicle (EV) design. Rivian developed the all-new Enduro drive unit in-house, replacing the earlier R1T quad motor system with a simpler, more cost-effective, high-performance solution. In this teardown, Munro & Associates breaks down the key design decisions. The result? A drive unit that’s not only backward-compatible but also leaner and better suited for real-world use.
Designed with lean manufacturing and simplified serviceability in mind, the Enduro drive unit provides a unique opportunity for automotive engineers, EV enthusiasts, and forward-looking investors to study Rivian’s evolving architecture. Let’s take a closer look at its structure, systems, and competitive edge.
From Bosch to In-House: Why the Enduro Matters
When Rivian launched its R1T with a quad motor configuration—two motors per axle—it relied on a Bosch-supplied drive unit. The Enduro unit changes the game by bringing production in-house. This shift enables greater control over cost, design, and scalability.
The Enduro setup uses two identical drive units—one front, one rear—each with a single motor, hence the term “dual motor.” Though horsepower is reduced compared to the quad motor system (665 hp vs. 835 hp), most drivers won’t notice the difference. Instead, they’ll benefit from reduced vehicle cost, improved efficiency, and substantial weight savings.
A Closer Look at the Motor and Rotor
At the heart of the Enduro is a permanent magnet AC motor with a hairpin-wound stator. The hairpin design, which simplifies assembly and minimizes welds, is becoming the industry norm for modern EVs. It stacks favorably against designs seen in the Ford Lightning, offering a clean, conventional layout optimized for manufacturability.
The rotor employs a V-shaped embedded magnet configuration, with its laminations offset to reduce cogging and enhance smooth power delivery. While technically conventional, the cooling strategy in this unit sets it apart.
Oil Cooling: A Leap Forward in Thermal Management
Rivian’s Enduro drive unit stands out for its pressurized oil cooling system. This marks a major upgrade from the glycol-only setup in the earlier quad motor variant. With this change, Rivian joins industry leaders like Tesla, who have long used oil cooling to boost thermal performance.
Key elements of the Enduro cooling strategy include:
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Hollow rotor shaft: Not just for weight savings—this channel routes oil directly into the rotor, where small nozzles spray it internally.
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External oil pump and filter: These maintain pressure and cleanliness, supporting the long-term performance of the system.
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Integrated heat exchanger: This plate-style exchanger routes glycol on one side and oil on the other, removing excess heat efficiently.
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Targeted oil jets: These are positioned to directly cool the copper conductor bars and rotor shaft, bathing high-heat components in oil.
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Integrated coolant flow paths: Coolant passes through jackets in the inverter and housing, minimizing thermal losses with clever internal routing.
This enhanced cooling supports higher performance levels and greater longevity without sacrificing weight or packaging.
Packaging and Backward Compatibility
A key design challenge was making the Enduro unit backward compatible with existing R1T platforms. To achieve this, Rivian retained the original mounting points while transitioning from extruded to cast housing. The result? Fewer parts, tighter integration, and seamless vehicle interface.
The stator and rotor housing features clever space utilization—including a triangular standoff section—to preserve access to components like the heat exchanger and resolver.
Despite using a single motor per axle, the packaging maintains a four-point mounting system identical to the original quad motor setup. That means Enduro-equipped vehicles can be built on the same production line without major retooling.
Differential and Drive Strategy: From Independent to Shared Torque
Unlike the quad motor setup where each wheel had its own motor (allowing full independent torque vectoring), the Enduro drive unit introduces a traditional differential. This gear set enables a single motor to drive both wheels on an axle while allowing them to rotate at different speeds—critical for cornering.
To preserve efficiency, Rivian also integrated a disconnect mechanism into the drive unit. This allows the motor to decouple from the wheels, reducing drag from back electromotive force (back-EMF) during coasting or when power isn’t needed.
This disconnect mechanism features:
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Electromagnetic actuation for smooth engagement and disengagement.
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Compact packaging integrated into the ring gear assembly.
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Spring washers and spline interfaces for robust, low-cost functionality.
This design mirrors strategies from Hyundai’s E-GMP platform and Mercedes-Benz, confirming Rivian’s alignment with industry best practices.
The Inverter: Efficient, Smarter Packaging
The inverter—responsible for converting battery DC power into three-phase AC for the motor—is built directly into the top housing. This integrated approach simplifies sealing, lowers cost, and improves heat management.
Notable features include:
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Compact layout with power switching components, capacitor, and current sensors on a single plane.
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Heat sinks cast into the base for effective thermal transfer.
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Seamless connection points between the inverter and stator, reducing resistance and simplifying assembly.
Compared to the previous design, this is a leap forward in cost and assembly efficiency, echoing Tesla’s cast inverter strategies.
Performance vs. Value: A Smart Tradeoff
The Enduro drive unit is roughly 30 kg lighter per unit—60 kg savings in total—compared to the quad motor equivalent. Despite the lower torque (approximately 10% less) and horsepower (about 20% less), real-world driving impact is negligible for most users.
Crucially, the cost savings are significant:
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$8,000 less for the base dual motor compared to quad.
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$3,000 less for the performance dual motor trim.
With fewer parts, reduced assembly complexity, and enhanced thermal management, the Enduro drive unit hits a sweet spot of performance, cost, and efficiency.
Final Thoughts: Leaner, Smarter, Ready to Scale
Rivian’s new Enduro drive unit signals a maturation of its EV architecture. The transition to an in-house, pressurized oil-cooled, and inverter-integrated system reflects a clear focus on lean design, manufacturability, and cost control.
While EV purists may miss the micro-level torque vectoring of quad motors, most drivers—and investors—will welcome the Enduro’s intelligent engineering and competitive edge.
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