In the automotive world, everyone else talks about cars, but I analyze the trends! If you've watched the launch events for this year's series of domestic high-end new energy vehicles, you'll notice a shift in what manufacturers are competing over. A few years ago, the battle was all about refrigerators, TVs, and large sofas. Later, the focus shifted to how many LiDAR sensors or how many TOPS of computing power the chip had. This year, however, things have changed again. The chassis, which used to be a single slide in a presentation lasting just over ten seconds, is now a topic car companies are eager to discuss for half an hour. This is because everyone is starting to realize that no matter how smart the intelligent driving system is, it ultimately relies on the chassis for execution. Seeing with sensors and computing with the brain is one thing, but whether the car can brake in time, turn precisely, and control its posture well is what truly determines the experience and safety.
Li Auto, NIO, XPeng, and IM Motors—the flagship domestic new energy vehicles launched this year—have all, without exception, made a previously unfamiliar term a key part of their marketing: the steer-by-wire chassis.
Understanding the Steer-by-Wire Chassis
First, let's review the traditional chassis. Its working principle is simple: you turn the steering wheel, a steering column turns the wheels; you press the brake pedal, hydraulic pressure pushes the brake calipers; you hit a pothole, the suspension spring compresses and rebounds. In essence, it moves as you command, with all components mechanically linked. This system has been used for over a century—mature, stable, and reliable. Even if the electronic systems fail, the mechanical structure remains. However, all components operate independently: the steering wheel handles steering, the brakes handle deceleration, and the suspension handles damping, with no communication or awareness of each other's actions.
Enter the steer-by-wire chassis. It replaces mechanical connections with electronic signals, controlling steering, braking, and suspension electronically. Moreover, the components on the chassis are no longer just ordinary mechanical parts; they are more accurately described as electronically controlled actuator systems. The steering system is called SBW (Steer-by-Wire), where the steering wheel has no physical connection to the wheels, and instructions are transmitted via electrical signals. The braking system is called EHB (Electro-Hydraulic Brake) or EMB (Electro-Mechanical Brake). EHB still uses an underlying hydraulic system but manages it electronically, while EMB is more radical, using electric motors to directly control the calipers, allowing independent braking for each wheel. There's also steer-by-wire suspension, like 800V fully active suspension, and steer-by-wire drive systems like wheel-side motors.
This is akin to giving the chassis a nervous system, centrally controlled by the chassis domain controller—the "brain." The entire chassis's operational logic becomes: human input to sensors, sensors to the controller, and finally the controller to the actuators. In other words, when you turn the steering wheel now, there isn't necessarily a physical steering column connected to the wheels; when you press the brake, it's not necessarily the hydraulic system working directly. In a car with a steer-by-wire chassis, you are merely issuing a command; the real work is done by the computer, with all electronically controlled actuator systems networked and coordinated.
However, it's crucial to clarify that the key to steer-by-wire isn't just electronic control—that's not new, as internal combustion engine vehicles also have electronic controls. The real change lies in two things: disconnection and integration. Disconnection means removing the direct mechanical hard link between the steering wheel, pedals, and the chassis actuators, allowing the computer to take over vehicle control more thoroughly. Integration means placing the drive, brake, steering, and suspension systems into the same control model, so they no longer operate as four separate departments but allow the entire vehicle to act as a cohesive whole.
The Drive Towards Steer-by-Wire Chassis in New Energy Vehicles
Why are new energy vehicle manufacturers now competing over steer-by-wire chassis? Many have realized that after competing on batteries, intelligent driving, and cabins, what may truly limit the development of autonomous driving is no longer computing power or sensors, but the chassis. The traditional car chassis is essentially designed for human drivers, with mechanical connections that have play, wear, and delay, and systems that operate relatively independently. This isn't a major issue for human drivers, but for an autonomous driving system that needs to compute hundreds or even thousands of times per second, this architecture is somewhat like the roads in an old city district—functional but not efficient enough.
The steer-by-wire chassis is more like an urban road renovation project. It digitizes and makes electronic the steering, braking, driving, and suspension systems. When the driver presses the pedal, it's no longer a mechanical structure directly at work but an electrical signal issuing a command. Steering, braking, and suspension can all be centrally coordinated by the main computer. What used to be four separate departments is now a single commander coordinating everything.
This way, when the autonomous driving system detects danger ahead, it can not only decide to decelerate but also simultaneously determine the steering angle, body posture, suspension stiffness, and power output. The entire vehicle moves as one unit, rather than multiple systems responding individually. This level of reaction speed and coordination far surpasses that of traditional chassis structures. Therefore, many industry insiders believe that a steer-by-wire chassis is not just a feature but an infrastructure. It's like building highways or laying fiber optic networks—usually invisible, but all future high-level intelligent driving, unmanned vehicles, and even cars without steering wheels and pedals must be built upon this architecture.
Advantages of Steer-by-Wire Chassis
The first and most immediate benefit is weight reduction, which was the original purpose of steer-by-wire technology. In 1981, the Space Shuttle Columbia first replaced steel cables and hydraulic lines with electrical cables, marking humanity's first use of steer-by-wire technology to replace traditional hydraulic transmission control systems—all to reduce weight. For cars, it's the same. The mechanical structures of traditional chassis take up a lot of space, such as the steering column, master brake cylinder, hydraulic mechanisms, and a multitude of pipes, which together are bulky and heavy.
What is the biggest issue with new energy vehicles? Batteries are getting larger, and vehicle weight is increasing. A battery can account for 20% or more of a car's weight. Under consumer demand for longer range, engineers are forced to keep increasing battery capacity—80 kWh, 100 kWh, 120 kWh—leading to a vicious cycle. Reducing battery weight is extremely difficult, as consumers complain about reduced range, so the focus shifts to the chassis.
Thus, engineers began this renovation project, electrifying wherever possible to shave off weight bit by bit. Steer-by-wire steering removes the steering column, replacing dozens of kilograms of steel with a cable; steer-by-wire braking eliminates the hydraulic system, with motors directly driving the calipers... According to industry estimates, a steer-by-wire chassis can reduce the vehicle's overall weight by 15-20% and extend range by 5-8%—an epic enhancement.
But weight reduction is just a side benefit. The real game-changer, as mentioned earlier, is paving the way for future L3 and even L4 level autonomous driving. In fact, the various chassis functions seen in current domestic high-end new energy vehicles are a prelude to computers taking over car control. For example, rear-wheel steering, where the rear wheels turn in the opposite direction at low speeds, making a large vehicle suddenly as agile as a small car, and turn in the same direction at high speeds, greatly enhancing high-speed stability; or tank turn, where all four motors and chassis systems work simultaneously; or crab walk mode, where wheels, which previously could only move forward and backward, now have independent control. These functions demonstrate the computer's control over the vehicle, of course, premised on the steer-by-wire chassis acting as the intermediary.
Looking further ahead, if drive motors, brake motors, steering motors, and active suspension actuators become further independent, the car's chassis will increasingly resemble a motion platform that can be finely controlled. In the past, we said cars were driven by people; in the future, the car may manage its own body. It will know how much force each wheel should apply, which side needs more braking, whether to lower or raise the body, and when to be stable or agile. Steer-by-wire is just the beginning, leading towards an era of AI integration. Some automakers have already started promoting concepts like vehicle-side AI agents or chassis intelligence entities. The AI here isn't a chatbot; the AI Agent discussed in the industry now essentially integrates the steer-by-wire chassis, intelligent driving AI, and intelligent cabin AI. This way, AI not only becomes an assistant that understands user needs and intentions but, where regulations permit, can also become the owner's dedicated driver. It will evolve, think, remember your preferences, and even optimize your poor driving habits.
This would greatly enhance vehicle safety and comfort. A human detecting danger takes at least half a second to react, while AI can do it in milliseconds. AI can also adjust the suspension in advance, distribute power ahead of time, and correct steering early, allowing the vehicle to prepare optimally for different scenarios and road conditions. However, this also means that our control over the car is diminishing, until eventually, the car controls itself completely—full autonomous driving.
When Will Steer-by-Wire Chassis Become Commonplace?
It's important to clarify here: having just one of steering, braking, or suspension be steer-by-wire does not constitute a steer-by-wire chassis. Remember, Infiniti Q50 was equipped with "DAS steer-by-wire steering" a decade ago, and Bosch developed a prototype for steer-by-wire braking over a decade ago. The current common understanding is that only simultaneous implementation of steer-by-wire steering, braking, and suspension qualifies as a steer-by-wire chassis, or a full steer-by-wire chassis.
The earliest model that could truly be called a steer-by-wire chassis is likely the NIO ET9 launched in 2024. It is one of the earliest domestic representative models to integrate steer-by-wire steering, rear-wheel steering, and fully active suspension into a mass-produced vehicle. It also received the Ministry of Industry and Information Technology's first mass-production license for steer-by-wire steering and the mandatory E-Mark certification from the European Economic Commission and the European Union. It is also one of the earliest domestic mass-produced cars to eliminate the mechanical steering column.
This year is precisely when steer-by-wire chassis technology is exploding, dubbed the "Year One of Steer-by-Wire Chassis" in the industry, for two reasons. First, on the regulatory front, starting July 1, 2026, the new national standard "Basic Requirements for Automotive Steering Systems" will officially take effect, removing the mandatory requirement to "retain a mechanical connection." This provides regulatory space for the mass production of electronically controlled actuator systems without mechanical backups, such as SBW steer-by-wire steering and EMB steer-by-wire braking. Second, on the technical front, the response times of core systems like steer-by-wire steering, braking, and suspension have now been compressed to the millisecond level. Through multiple redundancy designs like dual ECUs, dual power supplies, and dual communication, they meet the highest safety level ASIL-D in the international automotive functional safety standard.
So, you'll notice many models with steer-by-wire chassis this year. Various high-end new energy brands are piling features like steer-by-wire steering, steer-by-wire braking, rear-wheel steering, and active suspension onto their flagship models. It's not just domestic high-end new energy vehicles; foreign automakers are also working on steer-by-wire, albeit less aggressively. For instance, the new Mercedes-Benz EQS offers optional steer-by-wire steering, its first mass-produced model with this feature. Additionally, the long-wheelbase version of the BMW iX3 is equipped with a "Driving Control Super Brain" central domain control unit, which is more about software integration than full steer-by-wire hardware.
It can be said that steer-by-wire chassis will be a necessity for future high-end new energy vehicles. However, constrained by cost, it will likely only appear on flagship models in the coming years, with prices basically starting around 500,000 yuan. The industry estimates it will take at least three more years to trickle down to the 200,000-300,000 yuan market.
Who Holds the Key Steer-by-Wire Chassis Technologies?
At this point, you might think domestic automakers are unbeatable in steer-by-wire chassis technology? Not exactly. In fact, many core technologies are still held by foreign suppliers. In other words, these domestic car companies are more users and integrators of the technology.
Starting with SBW steer-by-wire steering, core suppliers include Bosch, ZF, and JTEKT (originally a Toyota-affiliated steering supplier). Domestic suppliers entered this field relatively late, with most still in the R&D or small-scale production stage. Nexteer is the only domestic supplier to achieve scaled mass production, securing orders from Tesla, as well as Li Auto, Zeekr, and Xiaomi. However, many don't consider it a purely domestic manufacturer, as it is a Chinese-controlled multinational enterprise whose predecessor was a company spun off from General Motors. Additionally, there's Zhejiang Shibao, whose first mass-production steer-by-wire steering project is expected to start production in the second half of 2026.
Moving on to steer-by-wire braking, Bosch still dominated in 2024, holding a staggering 53.7% market share, as expected from a traditional chassis supply giant. Others include Korea's Mando, Germany's Continental, and ZF, holding 7.3%, 4%, and 1.6% respectively. Domestic suppliers together account for about 32.57%.
Currently, EHB is the mainstream for steer-by-wire braking. Besides Bosch and Continental, a notable domestic supplier is Wuhu Bethel. For the next-generation EMB, domestic and foreign manufacturers are at roughly similar levels. Domestic companies like Bethel, Coordinate System Technology, and Like Technology have already entered mass production or small-batch delivery stages. Among them, Coordinate System's EMB is already installed on the Exeed EX7, claimed to be the world's first mass-produced passenger car equipped with EMB. Bosch and Continental's mass production plans are even scheduled for after 2027.
Then there's steer-by-wire suspension, which is currently the area where domestic suppliers excel the most. If looking only at air suspension, in 2025, just three companies—Top Group, Konghui Technology, and Baolong Technology—already hold nearly 90% of the combined market share. But steer-by-wire suspension isn't that simple, as air suspension or CDC is only part of it. Foreign companies like ZF and Continental, and domestic ones like Jingxizhixing, also have strong capabilities in various sub-fields of steer-by-wire suspension.
The biggest weakness for domestic suppliers, as many might guess, is chips. For example, in EHB steer-by-wire braking, the control electronics are one of the highest-value core components, and the automotive-grade MCU chips within them still heavily rely on overseas suppliers, including Infineon, STMicroelectronics, NXP, Renesas, etc. Although domestic suppliers have made rapid progress in various mechanical hardware in recent years, in areas like high-end automotive chips, functional safety, and underlying control software, they still lag somewhat.
So, from an industrial perspective, the steer-by-wire chassis isn't just about automakers competing on features; behind it lies the Chinese automotive industry catching up on the foundational subject of chassis technology.
Why Can't Internal Combustion Engine Vehicles Adopt Steer-by-Wire Chassis?
Many might wonder, since steer-by-wire chassis is so advanced, why don't internal combustion engine vehicles adopt it? At most, they might implement steer-by-wire steering? There are several reasons. First and foremost, the electrical architecture differs too much. Traditional internal combustion engine vehicles primarily used 12V systems, later upgraded to 48V mild hybrid. However, steer-by-wire chassis require higher power, faster data transmission, and more stable power supply capabilities. The 48V "pony" is simply not suited to pull the "large cart" of a steer-by-wire chassis. New energy vehicles are different; many are built on 800V high-voltage platforms, giving them a natural advantage.
Second, internal combustion engine vehicles carry too much mechanical baggage. Components like the engine, transmission, and drive shaft have been used for over a century, with the entire architecture designed around mechanical structures. Changing it now would be like removing load-bearing walls after a house is built—extremely troublesome.
Third, the demand for intelligence differs. As mentioned earlier, the greatest value of a steer-by-wire chassis isn't necessarily a more comfortable drive but laying the foundation for future autonomous driving. Many internal combustion engine vehicle users themselves aren't highly concerned with intelligent driving, so automakers naturally have little incentive to invest such high costs.
Potential Risks of Steer-by-Wire Chassis
Please don't misunderstand this as blind endorsement of the technology. Steer-by-wire steering is indeed the future direction, replacing the mechanical connection between the steering wheel and wheels with electronic signals and actuator control. But herein lies the problem. In the past, that steering column behind the wheel was the simplest thing, yet also the most reassuring. Now, with that hard connection removed, the sense of security no longer comes from the mechanics itself but from sensors, motors, power supplies, controllers, software algorithms, and an entire set of redundancy designs.
The Tesla Cybertruck serves as a stark reminder. It was very aggressive, featuring steer-by-wire steering, a 48-volt low-voltage architecture, rear-wheel steering, multi-sensor verification, dual power supply paths... However, a Cybertruck purchased by the authoritative American automotive media Edmunds for testing experienced a serious steering warning during evaluation. The rear-wheel steering was disabled, the vehicle speed was limited to an extremely low state, and it required multiple restarts to recover. Later investigation suggested the issue might not have been a failure of the steering motor itself but insufficient coolant, air in the lines, and the pressure sensor giving the system an erroneous reading, ultimately triggering a protective strategy in the algorithm.
The most alarming aspect of this incident isn't whether the Cybertruck actually broke down, but rather who its control logic prioritizes protecting in critical moments. From an engineering standpoint, if the system detects the steering motor might overheat, of course it should prevent further hardware damage, and limiting vehicle capability has its rationale. But from the driver's perspective, the vehicle hasn't completely lost control, the person is still inside, yet the system makes the decision first, locking the car into a protective mode and leaving the driver to deal with the consequences slowly. With traditional mechanical steering, even if the power assist fails, the driver can still forcefully turn the wheel, gritting their teeth to move the car to a safe area.
Simply put, the scariest thing about future cars isn't that the computer can't make judgments, but that it judges too quickly and decisively, and its first reaction might not be to ensure your safe exit but to ensure the system itself shuts down safely. The introduction of the new national steering system standard is certainly progress. It incorporates mandatory requirements for steer-by-wire steering failure degradation, fault alarms, and hazard avoidance capability after power loss. For example, after a fault, power assist cannot be cut off immediately, leaving the driver time to take over and pull over; after a main power supply failure, remaining energy must support the vehicle in performing continuous evasive maneuvers... These requirements are crucial because they at least tell automakers that steering is not a function where slow trial and error is acceptable; behind the steering wheel sits a person, not a test device in a lab.
But national standards only set the engineering baseline; they don't guarantee that automakers will fully back consumers. If an accident occurs in the future, the automaker could very well say the product met standards and the situation was an extreme condition. The supplier might say the component passed tests, the software company might say the logic was normal, and the chip manufacturer might say the hardware didn't fail. Each link alone might be compliant, but combined, they could still cause problems, leaving the consumer in the most difficult position. This is the real issue that needs highlighting with steer-by-wire chassis. It's not that it shouldn't develop, but that risks shouldn't be glossed over with just the word "advanced." As technology moves forward, responsibility must also move forward.
Conclusion
Ultimately, traditional cars follow a "human—mechanics—car" logic, with steering, braking, and suspension operating independently. The steer-by-wire chassis transforms mechanical connections into electronic signals, creating a new "human—sensors—controller—actuators" model. Its greatest significance isn't just weight reduction or space saving, but turning the car from a mechanical product into an intelligent entity capable of autonomously controlling its own body. Rear-wheel steering, tank turn, crab walk mode... these seemingly flashy functions are essentially the computer beginning to uniformly coordinate vehicle movements. In the future L3 and L4 era, the real competition among vehicles might not be who goes faster, but who better controls their own body.
But finally, I'd like to pour some cold water. The steer-by-wire chassis certainly represents the future, but the future doesn't equal zero risk. The more mechanical connections are handed over to electrical signals, the more driving actions are entrusted to algorithms, the clearer automakers must be about responsibility. Who controls the data, who explains faults, who bears compensation, who provides the ultimate guarantee—if these issues aren't resolved, consumers will always have doubts. Because for automakers, this is the next-generation chassis architecture, but for the person sitting in the car, it's their own steering wheel and brakes.
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