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The all-new 2025 Rivian R1S might look familiar from the outside, but beneath its body lies a range of undercarriage upgrades that mark a pivotal step in Rivian’s engineering evolution. Recently, the Munro team conducted a detailed teardown comparison between the original R1S and its Gen 2 counterpart. Their analysis spotlights significant revisions to the cradle, suspension, battery protection, and casting strategies—all of which reflect Rivian’s growing maturity in electric vehicle (EV) design and manufacturing efficiency.
Let’s explore the key structural innovations that make the Rivian R1S Gen 2 a benchmark in smart, scalable EV architecture.
Cast Cradle Evolution: From Stamped to Single-Piece Integration
One of the most critical changes is the redesigned front cradle. The Gen 1 R1S featured a highly complex assembly made up of extrusions and stamped aluminum, requiring over 25 individual components and extensive welding. While suitable for early-stage production, this design was costly and labor-intensive.
In contrast, the Gen 2 vehicle features a single-piece cast aluminum cradle. This design consolidates attachment points for control arms, the electric drive module (EDM), and even the radiator. The casting simplifies manufacturing, improves structural rigidity, and trims down the bill of materials—key for Rivian as it scales production.
The shift also signals a commitment to capital investment in tooling and long-term efficiency, much like Tesla’s move toward giga-casting. It’s a bold but necessary step for Rivian to hit profitability targets.
Knuckle Optimization and Structural Refinements
The Munro team engineers highlight notable weight-saving measures in the revised knuckle. Where the original version retained excess aluminum in non-critical areas, the Gen 2 opens up internal pockets and slims down the base structure. These changes reflect the results of extended durability testing post–Job One, which allowed Rivian engineers to validate safety margins and remove redundant material.
Such iterative design—evolving after initial production—is a hallmark of adaptive lean engineering. Rivian is learning quickly, and they’re not afraid to implement aggressive improvements mid-cycle.
Active Hydraulic and Air Suspension Integration
Rivian’s sophisticated suspension system remains a standout feature, but the integration has matured. Both generations offer a dual-system setup—hydraulic damping for real-time ride control and air suspension for height adjustability.
Notably, in the front, the hydraulic and air assemblies are co-located, whereas in the rear they are split into separate components. This architecture eliminates the need for traditional sway bars, reducing weight and mechanical complexity while maintaining excellent handling characteristics.
This innovative suspension approach not only enhances off-road performance but also improves on-road comfort—delivering dynamic stiffness control that rivals luxury SUVs.
Shear Plates and Crush Strategies: Safety-Driven Design
Another major improvement is in crash energy management. The Gen 2 adds two new shear plates between the front cradle and the battery pack. Their dual-part configuration could be the result of late-stage reinforcement or may be a deliberate design to shear in controlled ways during impact.
The Munro team speculates that this split-joint system may allow the cradle to decouple during a frontal collision, preventing the powertrain from intruding into the cabin. It’s a safety strategy reminiscent of older BMW designs, refined for the EV age. The EDM is suspended via elastic mounts while the cradle ramps downward—creating optimized crush space in the event of a crash.
This nuanced approach to collision engineering shows how seriously Rivian takes occupant protection, even as it retools the underbody architecture for mass production.
Battery Protection: From Carbon Fiber to Composites
Rivian’s Gen 2 undercarriage abandons the carbon fiber-reinforced shields of the R1T and early R1S in favor of more typical composites—possibly overmolded aluminum or reinforced polymers. The new non-magnetic shield offers sufficient impact protection without the cost and complexity of exotic materials.
This change reflects a maturing supply chain and a stronger focus on production scalability. By transitioning to simpler materials, Rivian reduces component costs while maintaining off-road durability.
Rear Undercarriage: Strategic Carryover Meets Subtle Refinement
In a surprising twist, the rear cradle remains largely unchanged from the original R1S. Despite moving to new in-house dual motors, Rivian preserved much of the Gen 1 rear suspension architecture, including the multi-link layout and aluminum control arms.
This reuse of validated components is a strategic win. It minimizes retooling, accelerates development timelines, and leverages proven parts to offset the costs of innovation elsewhere.
However, there are still changes: the rear motor’s noise/vibration/harshness (NVH) insulation now uses a foam core with a rigid shell, likely to improve frequency damping while protecting against road grime. And the rear-most fascia shield switches to a standard resin instead of premium fiber-reinforced plastic—another small but telling optimization.
Battery Pack Rear Casting: A Major Structural Leap
Perhaps the most impressive update is the casting that now forms the rear face of the battery pack. This replaces a heavily machined, extrusion-based structure previously sealed with RTV and butyl tape. The casting now provides integral mounting points for connectors, vents, and coolant lines, sealed cleanly with structural adhesives.
This shift to high-integration casting mirrors the cradle’s redesign, cutting manufacturing steps and boosting rigidity. It also signals Rivian’s increasing sophistication in battery pack architecture—an area where every gram, millimeter, and second on the production line counts.
Takeaways: Rapid Learning, Smart Scaling
The Rivian R1S Gen 2 undercarriage isn’t just an update—it’s a case study in rapid iteration, lean design, and intelligent platform evolution. From structural castings to modular suspension and crash strategies, every change reflects a deeper understanding of both product and process.
For investors, engineers, and EV enthusiasts alike, the Gen 2 R1S is proof that Rivian is not standing still. They’re refining their vehicles with Tesla-like agility, while carving out a distinct, adventure-ready identity. As the company pushes toward profitability, expect more architectural breakthroughs—not just in function, but in manufacturability.
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