DRY BRAKE-BY-WIRE: The Next Chassis Era

For decades, the operating principle of a conventional vehicle braking system was straightforward.

The driver pressed the brake pedal, the booster amplified the input, hydraulic pressure moved through the brake lines, the caliper clamped the disc, and the vehicle’s kinetic energy was converted into heat.

This architecture remains highly reliable and has created one of the most mature aftermarket categories in the automotive industry. Brake pads, discs, calipers, master cylinders, hoses and related service components are widely understood by distributors, repair shops and technicians around the world.

However, electrification, advanced driver assistance and software-defined vehicle architectures are changing the role of the braking system.

Braking is gradually evolving from a mechanical-hydraulic subsystem into an electronically managed motion-control function involving sensors, controllers, actuators and software.

That transition is becoming increasingly visible in 2026. Bosch has disclosed that its hydraulic brake-by-wire solution has secured supply contracts with several vehicle manufacturers and is expected to enter passenger-car volume production in mid-2026. ZF and Nexteer are also expanding their brake-by-wire, electro-mechanical braking and integrated motion-control portfolios.

The implications go beyond vehicle performance. They will also affect aftermarket diagnostics, parts identification, technician training and international supply-chain management.

Conventional hydraulic braking systems became dominant because they offered a practical balance of reliability, cost, performance and serviceability.

A typical system includes:

• Brake pedal
• Brake booster
• Master cylinder
• Brake fluid
• Hydraulic lines
• Brake calipers
• Brake discs or drums
• Brake pads or shoes

The driver’s input is converted into hydraulic pressure and transmitted to the wheel-end braking hardware.

This architecture has several advantages:

• It is well understood by vehicle manufacturers and repair technicians;
• The main components are standardized across large vehicle populations;
• Maintenance procedures are established;
• Failure modes are relatively familiar;
• The aftermarket has a mature supply chain.

Common diagnostic and repair activities include checking pad wear, disc condition, caliper operation, fluid leakage, air in the lines and master-cylinder performance.

Brake-by-wire is therefore not emerging because conventional hydraulic brakes are fundamentally unreliable.

It is emerging because the next generation of vehicles requires tighter coordination among braking, regenerative energy recovery, stability control, automated driving and vehicle motion management.

Brake-by-wire does not simply mean replacing the brake pedal with an electronic sensor.

Its deeper purpose is to redefine the relationship between driver input and wheel-end braking force.

In a conventional system, the pedal input is directly connected to the mechanical and hydraulic process that generates braking force.

In a brake-by-wire system, the driver’s request is first detected electronically. A controller then calculates the required deceleration using information such as vehicle speed, wheel speed, acceleration, stability status, regenerative-braking demand and road conditions. The braking actuator then executes the command.

The control chain becomes:

Driver input → sensor detection → software calculation → actuator response → vehicle deceleration

This architecture is well suited to integration with:

• Anti-lock braking systems;
• Electronic stability control;
• Automatic emergency braking;
• Adaptive cruise control;
• Automated parking;
• Lane-keeping and evasive steering systems;
• Regenerative braking;
• Centralized vehicle motion management.

The key value of brake-by-wire is therefore not simply the reduction of hydraulic plumbing.

It is the conversion of braking into a software-controllable vehicle-motion function.

Brake-by-wire is not one single technology. It is a group of architectures with different levels of electronic and mechanical integration.

Hydraulic brake-by-wire retains part of the conventional hydraulic foundation but manages braking through electronic signals and electrically controlled actuation.

Its advantages include:

• Strong use of existing braking technology;
• Compatibility with familiar discs, pads and calipers;
• Easier adaptation to different vehicle platforms;
• A relatively manageable transition path for OEMs.

Bosch says its hydraulic brake-by-wire solution combines a newly developed brake actuator with a traditional ESP system. The company has reported supply contracts with five manufacturers and expects volume production in passenger cars from mid-2026.

Electro-mechanical braking, commonly referred to as EMB, represents a deeper shift toward wheel-end electronic actuation.

An EMB system uses an electric motor and mechanical transmission at the wheel to generate clamping force. In principle, this can significantly reduce or eliminate the need for a conventional centralized hydraulic system.

Nexteer stated in 2026 that its EMB technology had completed development and validation and had reached market readiness. The company has positioned EMB alongside steer-by-wire within its broader Motion-by-Wire portfolio.

ZF has described a dry brake-by-wire approach that does not require brake fluid. This has the potential to change the traditional maintenance logic built around hydraulic lines, fluid replacement and bleeding procedures.

From an engineering perspective, dry brake-by-wire may enable:

• Greater flexibility in chassis packaging;
• More direct electronic control;
• Easier integration with software-defined vehicle architectures;
• More precise individual-wheel braking;
• Closer coordination with steering, propulsion and suspension systems.

At the same time, it requires robust functional safety, redundant power supply, fault detection and actuator reliability.

The relationship between electric vehicles and brake-by-wire is deeper than the simple fact that EVs use more electronics.

Electric vehicles have fundamentally different deceleration requirements.

A modern EV may combine:

• Regenerative braking through the drive motor;
• Friction braking;
• Anti-lock control;
• Vehicle stability management;
• Battery state-of-charge constraints;
• Motor temperature and power limits.

If these functions remain separated within a conventional control architecture, the vehicle cannot optimize the available braking sources as effectively.

Brake-by-wire allows software to distribute braking force dynamically.

For example:

• When the battery can accept more energy, regenerative braking can be increased;
• When road adhesion is poor, braking force can be adjusted at individual wheels;
• During emergency braking, stability can be prioritized;
• When ADAS intervenes, the system can issue an accurate braking command directly;
• During long downhill driving, regenerative and friction braking can be balanced;

The braking system therefore becomes more than a deceleration device.

It becomes an important node in both energy management and vehicle motion control.

Automotive chassis development is moving from isolated component optimization toward coordinated vehicle-motion control.

Nexteer groups steer-by-wire, brake-by-wire, rear-wheel steering and software functions within a broader Motion-by-Wire strategy. ZF is pursuing a similar direction through its Chassis 2.0 approach and software platforms that coordinate steering, braking, propulsion and suspension actuators.

When a vehicle combines steer-by-wire and brake-by-wire, more advanced control strategies become possible.

In an emergency-avoidance event:

1. Environmental sensors detect a hazard;
2. The vehicle controller calculates collision risk;
3. Brake-by-wire applies differentiated braking at the wheels;
4. Steer-by-wire adjusts the vehicle’s direction;
5. The propulsion system reduces or cuts drive torque;
6. Stability control continuously corrects the vehicle’s attitude.

This level of coordination is difficult to achieve through driver-operated mechanical systems alone.

As a result, brake-by-wire and steer-by-wire are likely to become two core actuation modules within an integrated intelligent chassis rather than separate product categories.

Brake-by-wire will not immediately eliminate conventional braking components, but it will change how faults are diagnosed and repaired.

Traditional brake service focuses on issues suchs as:

• Pad wear;
• Disc deformation;
• Caliper seizure;
• Hydraulic leakage;
• Air in the brake circuit;
• Master-cylinder or booster failure.

Brake-by-wire systems add new diagnostic requirements:

• Sensor signals;
• Actuator response;
• Controller communication;