Bosch's brake-by-wire system may be the next big leap in automotive tech

Safety and Reliability Concerns

• Many commenters reject brake‑by‑wire outright if there’s no mechanical backup. Brakes are seen as the one system that must still work with the engine off, battery dead, or electronics failed.
• People worry about “cliff” failure modes: chips, wiring, or CAN bus faults can fail instantly and completely, unlike hydraulic systems that often degrade gradually and remain partly functional.
• Edge cases discussed: alternator failure draining the battery while driving, shorts near the battery, crashes that cut power, or total electrical failure while still moving. In those scenarios, a purely electronic brake is viewed as unacceptable unless redundancy is extremely robust.

Mechanical vs Electronic Tradeoffs

• Supporters argue modern brakes are already complex: ABS, stability control, auto‑braking, radar/lane systems all add valves, pumps, sensors, and software on top of the “simple” hydraulic core. A clean-sheet brake‑by‑wire design might actually reduce overall complexity and enable better automated control.
• Critics counter that existing electronics assist but don’t break the direct hydraulic path from pedal to caliper; you can still stop if electronics die. Removing that last mechanical link is seen as a step too far.

Weight, Space, and Cost

• Skepticism that deleting a few millimeters of brake line meaningfully reduces weight or volume, especially on heavy EVs.
• Others note that even small per‑vehicle savings multiplied across millions of cars matter, and that assembly, plumbing, and variant reduction (one module instead of many left/right-specific parts) lower factory cost and complexity.
• Several comments assert the real driver is cost and ease of assembly, not consumer benefit.

Brake Feel and Driving Experience

• Loss of tactile feedback is a major complaint. With hydraulics, drivers can feel tire grip through the pedal; that’s both confidence- and safety-relevant.
• Reported experiences with existing brake‑by‑wire systems describe vague, “tennis ball” pedal feel.
• Some suggest feedback can be emulated with sensors and actuators, even personalized per driver, but others expect this to be cost‑cut over time.

Right-to-Repair, Lock-In, and Service

• Strong suspicion that integrated electronic brake modules will be dealer‑only, expensive, and model‑specific, worsening long-term repairability and parts availability.
• Bosch and German OEMs are criticized for proprietary tools, anti‑repair policies, and high service pricing; commenters expect similar behavior here.
• More electronics also shifts failures from cheap, generic parts to costly modules and harder diagnostics.

Regulation, Precedent, and Security

• Some believe brake‑by‑wire is currently illegal or tightly restricted in certain jurisdictions and would require rule changes.
• Past systems like Mercedes’ Sensotronic Brake Control are cited as cautionary tales: complex, failure‑prone, and ultimately abandoned despite backups.
• Another thread worries about cybersecurity: as connectivity and by‑wire controls spread, a compromise of the telematics unit plus CAN bus access could permit remote interference with brakes.