How Rivian Resolved the Tire Consumption Issue in the R1T and R1S

      Rivian

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      When Rivian initially introduced its quad-motor electric R1T pickup, early users encountered an unfortunate issue: the truck wore out tires at an excessive rate when operated in its eco “Conserve” mode. I’ll explain why this happened, but today’s big news is that Rivian has redesigned the system in the second-generation 2026 R1T and R1S Quads to alleviate this problem, at least for the new models.

      Similar to its 360-degree kick turn, the latest Quads feature both mechanical and software modifications that enable this improvement, meaning the less destructive Conserve mode won’t be available to existing vehicles through an over-the-air update. Essentially, while the previous system forced the heavy truck into front-wheel drive, the new version operates more like an automatic four-wheel drive system.

      The first-generation quad-motor R1s used four water-cooled motors from Bosch because Rivian's in-house Ascent motors weren’t ready yet. This reliance on external motors, combined with the initial wiring harness containing 17 ECUs, limited Rivian's precise control over the system, as stated by R1 Chief Engineer Luke Lynch.

      Consequently, when in Conserve Mode, the R1T and R1S completely disengaged both rear motors, converting the R1 into a 7,000-pound front-wheel drive tire-destroying vehicle. Additionally, the driveline was known to produce a concerning clunking noise (and sensation) during engagement or disengagement while in motion, an experience I encountered when testing the old model.

      2026 Rivian R1T chassis. Rivian

      For the second-generation Quad, Rivian has combined its new electrical architecture, featuring a zonal design with only 7 ECUs that was introduced in 2025, with the newly developed in-house oil-cooled Ascent motors.

      Vivek Surya, Rivian's Director of Product Management and Vehicle Applications, explained to The Drive that in Gen 1, the motor disconnections weren't as controllable. This limitation impacted the team's ability to achieve a balance among drivability, NVH (noise, vibration, and harshness), and efficiency.

      In the second-gen Quad, Rivian has improved Conserve Mode, making it more akin to automatic four-wheel drive in a pickup truck. Instead of simply shutting down the rear motors, the new system disconnects at highway speeds or 50 mph and above when high torque isn't needed. When additional torque is required, such as during acceleration from a stop or when passing on the highway, the rear motors quickly and quietly re-engage for four-wheel drive.

      By designing the system to re-engage the rear motors when needed, the second-generation Quads are expected to reduce front tire wear in Conserve Mode.

      The new system is also faster and more efficient when activating or deactivating. The front motors utilize a silicon carbide (SiC) inverter for improved efficiency, while the rear motors employ an IGBT inverter, which is less efficient. The front motor setup targets efficiency, while the rear is particularly geared towards power delivery.

      Surya confirmed that the revamped Conserve Mode functions the same way in the Tri-Motor R1T and R1S launched in 2025 as it does in the new second-gen Quads. However, the Dual-Motor models do not feature a specific Conserve Mode. Wassym Bensaid, Rivian’s Chief Software Engineer, informed The Drive that Dual-Motor models automatically engage and deactivate the single rear motor whenever possible in the All Purpose drive mode.

      Surya pointed out a significant distinction between the Dual-Motor variants and the Quad and Tri models regarding how the system manages drive modes upon vehicle startup. Quad- and Tri-Motor models will retain and default to the last used drive mode, except for Off-Road mode.

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