By Zhang Jin
The chassis is the baseline that most people overlook.
When choosing a car, most people make decisions about screens and sofas faster than they do about powertrain performance. While power determines how fast you can go, the chassis determines whether you dare to keep your foot on the accelerator. From internal combustion to electrification, the drive format has changed, but the iron rule of the chassis—catching and managing power—remains unchanged. If a car cannot even grip the ground, no matter how much horsepower it has, it is merely a prelude to losing control.
Chinese automakers have lacked a firm foothold in this domain for nearly two decades.
Steering, braking, and suspension, the three core systems of the chassis, were firmly controlled by European (and some Japanese) Tier 1 suppliers such as Bosch, Continental, and ZF during the ICE (Internal Combustion Engine) vehicle era. Chinese domestic brands either bought their black-box systems or paid European tuning companies to "tune" them—lacking the capability to lead the process themselves. As a result, product competitiveness was subject to the control of others, and the upper limit was locked by suppliers. There was no leverage to build cars with a genuine driving feel.
The shift began to emerge around 2022, with electrification handing China a key.
According to public data, in 2021, Bosch's market share for brake-by-wire in China exceeded 90%. In 2022, BETHEL's One-Box brake-by-wire products began mass production at scale, entering the supply chains of new forces like Leapmotor; in 2023, in-house solutions from Nasentech, Huawei, and BYD were implemented; entering 2024, the combined market share of domestic brake-by-wire systems exceeded 30%, while Bosch's share dropped to about 60%, all within just three years.
Prior to 2022, core components of air suspensions were long dominated by European suppliers such as Vibracoustic (ZF) and Continental, with domestic suppliers almost entirely absent from the high-end market. In 2022, KH-AutoTech rapidly rose to the top of the domestic air suspension market share, thanks to mass nominations from multiple new forces; by 2023, KH-AutoTech's share increased to about 44.5%, and the combined market share of KH-AutoTech and Baolong, two domestic suppliers, exceeded 65%. The incremental growth was almost entirely captured by domestic suppliers.
As the market share of European Tier 1 suppliers declined, the Chinese supply chain stepped in to fill the gap. However, a larger variable lies beyond the data: OEMs (Original Equipment Manufacturers) have begun to develop chassis in-house.
In-house chassis systems such as BYD DiSus, NIO SkyRide, and Huawei Tuling have erupted in a concentrated manner. These systems are no longer just integrations of procured components, but vehicle-level solutions with deep software-hardware integration, representing the leap of Chinese automakers from "using the chassis" to "defining the chassis."
The twenty-year-old high wall is crumbling.
01 From the ICE Era to Electrification: Multiple Breakthroughs of the Chinese Chassis
Returning to the starting point of China's automotive industry, in 1956, the first domestically produced Jiefang-brand truck rolled off the assembly line in Changchun. This was the first time Chinese people built a car entirely on their own, causing a nationwide sensation.
True large-scale commercialization began with the joint venture wave in the 1980s. China implemented the "technology for market" strategy, allowing foreign automakers to enter China and establish joint ventures in exchange for core technology transfers.
However, while foreign capital gained the market, the technology was not truly transferred. What Chinese OEMs learned was mostly assembly processes and partial body stamping techniques; core chassis technology remained firmly in foreign hands: vehicle platforms and tuning remained in the hands of Volkswagen and General Motors, while for core components, European Tier 1 suppliers like Bosch and ZF supplied them in a "black-box" manner.
For nearly a decade thereafter, Chinese domestic brands grew wildly in a state of "having a body but no soul," trading low prices for scale, and scale for survival. However, as sales increased, Bosch and Continental did not significantly lower their prices. The procurement cost of chassis electronic control systems accounted for a substantial proportion, pushing cost pressures to a critical point.
More fatally, the black-box mechanism of Tier 1 suppliers constrained OEMs at every turn in product iteration. If they wanted to change a single parameter, they had to go through a change process, which was lengthy, expensive, and sometimes directly rejected. The fiercer the competition, the deeper the constraints.
The triple overlay of cost pressure, passive constraints, and the need for brand upgrading awakened some domestic brands: they must build the chassis themselves.
However, despite some efforts and indeed making breakthroughs in chassis tuning and low-end braking components, Bosch and Continental remained immovable in the face of high-end electronic control systems. The technical barriers built by European Tier 1 suppliers over two or three decades were only touched at the edges by the efforts of domestic brands. That was until the electrification wave swept the globe, rewriting the rules of the game.
During the ICE era, the barriers of European Tier 1 suppliers in the chassis field stemmed from decades of accumulation in real mass production. Mechanical experience, road spectrum data, and safety certifications—each could only be grown from mass production; they could neither be bought nor bypassed.
After electrification, the underlying logic of chassis control was reconstructed. The dominance of control shifted from mechanical structures to electronic control, and the key variable determining chassis performance became "how smart the control algorithms are." The advantage of mechanical experience accumulated by European suppliers over decades was partially diluted.
Given that China has accumulated years of experience in software engineering and sensor supply chains, from this perspective, the starting point is much higher than in the mechanical era. Chinese enterprises were able to truly compete at the algorithm level relying on their software capabilities.
Meanwhile, Bosch and its peers faced a transformation dilemma. The "slow and steady" hardware system, the bundled delivery business model, and the rhythm established around safety certifications and calibrations built during the ICE era turned their advantages into burdens in the face of the new logic of software speed required by electrification and customers demanding algorithm sovereignty.
The transformation of Bosch and its peers takes time, and building algorithmic barriers also takes time. On these two time tracks lies precisely China's window of opportunity. Chinese enterprises need to dig a deep moat at the algorithm level before Bosch completes its transformation.
Chassis technology is an engineering discipline highly dependent on experience accumulation, but the carrier of "experience" is migrating from humans and hardware to software and data. Whoever completes this migration first can rebuild barriers in the next cycle. BYD DiSus, Huawei Tuling, and NIO SkyRide are products of this window period. The three companies have different genes and distinct routes, presenting three paths for the Chinese chassis.
BYD's route is a battery-led structural reconstruction. It does not start from the chassis to build the chassis, but uses the battery as the origin, extending control simultaneously upstream and downstream. The advantage lies in using strong vertical integration capabilities and cost control to rapidly mass-produce multiple technologies with moderate innovation density, establishing chassis barriers through scaled manufacturing. This is the physics school driven by manufacturing capabilities.
Huawei does not build cars itself, entering the intelligent driving field as a Tier 1 supplier. The biggest feature of its chassis is its integration with intelligent driving, using ICT capabilities to penetrate the perception and control layers of the chassis, merging intelligent driving with the chassis execution layer, turning the chassis into a physical interface programmable by algorithms. Huawei's approach is essentially lending the "eyes" of intelligent driving to the chassis, using information advantages to make up for the lack of control over the hardware supply chain; it does not manufacture parts, but through control algorithms and domain control architectures, it attempts to become an indispensable "brain" supplier for OEMs.
The divergence from BYD's route lies here: one grows upward from the physical structure, while the other permeates downward from software algorithms.
NIO SkyRide intelligent chassis takes the route closest to the forward development logic of traditional luxury car manufacturers, supported by the software capabilities that new forces excel at. Unlike BYD, which cuts in from the battery structure, or Huawei, which permeates downward with algorithms, it develops layer by layer in-house from execution hardware (integrated fully active suspension, steer-by-wire, rear-wheel steering) to chassis control (ICC), vehicle motion control (VMC), and then to the global operating system (SkyOS), forming a vertically integrated architecture with software-hardware synergy.
Under this architecture, when the intelligent driving system issues motion intentions, it can directly dispatch the chassis for millisecond-level responses, without going through the black-box translation of Tier 1 suppliers like Bosch and ZF in the middle—this is the core value of NIO's route.
02 The First Time Chinese Automakers Have the Definition Right of the Chassis
In this vertically integrated architecture with software-hardware synergy developed in-house by NIO, the ICC (Intelligent Chassis Controller) is the key breakthrough in breaking the "black-box" monopoly of European Tier 1 suppliers.
In early 2021, chassis engineer He Xian was deeply impressed by the launch of the NIO ET7, as it was equipped with NIO's full-stack in-house developed chassis domain controller (ICC).
At that time, for chassis systems such as air springs, air suspensions, and CDCs, other Chinese OEMs basically procured a fully integrated black-box solution directly from European Tier 1 suppliers like Continental and ZF—the internal control logic was not open to the outside, and OEMs could only call limited interface parameters without being able to modify the core algorithms.
This meant that when the dampers should be tuned hard or soft was decided by others; if they wanted to optimize for Chinese road conditions, they couldn't change it; if they wanted to link the chassis with their own intelligent driving systems, they couldn't connect them. If they wanted to change it, they had to pay; a tiny modification often required paying exorbitant development fees.
However, the NIO ET7 took the lead in achieving autonomy from hardware to control logic. This was not only a technological breakthrough but also a landmark event marking the transfer of chassis definition rights from European Tier 1 suppliers to Chinese OEMs.
The source of everything began with the NIO ES8 Founder's Edition. The first-generation ES8 gathered the world's top hardware at the time, including the chassis. The head of vehicle R&D and the head of procurement at the time traveled to Europe multiple times, visiting suppliers one by one and persuading them, before finally purchasing top-tier air suspension and steering systems.
The first-generation NIO ES8 already came standard with air suspension and CDC active electronic dampers.
However, after the delivery of the Founder's Edition ES8, car owners successively complained about the unstable and unpredictable performance of the air suspension. Some owners even wrote a nearly thousand-word long post on the NIO App calling it "Schrödinger's air suspension," which caused a huge response, with nearly 3,000 comments alone.
NIO Founder and CEO William Li issued an order at an internal meeting: at all costs, this problem must be solved as quickly as possible. The NIO chassis team and product experience team quickly set up the "Schrödinger Suspension" task force, but the problem was far more thorny than imagined.
Dampers and air springs each have their own control logic, and both are sealed within the supplier's controllers—this is the price of the "black box." If NIO's engineers wanted to adjust a damping parameter, they had to submit a request to the supplier and then wait for their scheduling, verification, and feedback. Sometimes, to optimize a subtle vibration filtering, both parties would tug-of-war for weeks.
Out of helplessness, late one night, William Li personally wrote an email to the global CEO of a top-tier supplier seeking cooperation. Subsequently, both sides set up a joint task force. NIO urgently gathered all suspension technology experts from San Jose, USA, Europe, and the Shanghai headquarters; the partner also re-dispatched senior engineers to fly to Shanghai. This tug-of-war lasted for more than two years before the chassis experience of the first-generation ES8 returned to the forefront of the industry.
The real lesson from the "Schrödinger Suspension" incident was not the technical difficulty, but the control right. The team realized that as long as the control logic remained locked in the supplier's black box, no matter how good the hardware was, it was just a bound shell.
The team began to ask a more long-term question: If we continue to rely on the black box, what will NIO look like in five years? The answer pointed to the in-house development of the Intelligent Chassis Controller (ICC), to give the "brain" absolute control over the "body."
However, international suppliers were unwilling to provide mechanical hardware separately, such as the crucial air springs. NIO then decided to find a supplier among domestic enterprises capable of mass-producing them independently. After some investigation, NIO found that no domestic air spring supplier had OEM experience. The only one had only done after-sales maintenance for BBA (BMW, Benz, Audi).
NIO Executive Vice President Shen Feng found the founder of this domestic manufacturer and asked: Are you willing to explore this field together? Do you have the determination to invest real money to build a factory? After receiving a firm answer, NIO decided to support this local supplier in starting a business from 0 to 1. NIO even helped interview the first batch of engineers they recruited.
Having resolved the constraints of key chassis hardware such as air springs, they still had to solve the physical carrier of the ICC "brain"—the domain controller hardware. To avoid black-box risks, NIO also found a domestic controller supplier.
The two sides formed a deeply cooperative joint team. This domestic controller supplier conquered the manufacturing processes of mechanical hardware (air springs) and electronic hardware (controllers) on both sides, while NIO injected the most core "soul"—full-stack in-house developed control software and system integration.
This cooperation was a "white-box model," with complete trust between both parties and shared technology IP.
In 2021, the ET7 equipped with the ICC was launched. This was China's first full-stack in-house developed intelligent chassis domain controller mass-produced in vehicles. The ICC turned the "black box" of European suppliers into a "white box," allowing NIO engineers to finally bypass suppliers, directly modify parameters, deploy algorithms, and develop at the domain controller level. From then on, the chassis, like a smartphone, possessed the capability for OTA (Over-The-Air) evolution.
This was the first time Chinese automakers broke the monopoly of international giants in the ICC field. The ICC ended the era of "isolated islands" in chassis hardware and served as the technical foundation for all subsequent capabilities such as FOTA, multi-actuator coordination, and personalized tuning. Without in-house ICC development, everything else would be castles in the air.
The price of NIO's approach is a long R&D cycle and high costs, but in exchange, it gained the independent definition right of the chassis that China had always lacked during the ICE era.
03 From Passive Breakthroughs Under "Black Box" Constraints, to Proactive Strikes on Core Technologies
If NIO's in-house development of the ICC was a passive breakthrough under the constraints of the black-box systems of European Tier 1 suppliers like Bosch and ZF, then the development of the integrated hydraulic fully active suspension was a proactive strike by NIO at the commanding heights of core technology.
In 2022, the ET9 project was launched. The NIO chassis team began to discuss a more radical question: What more can be done for the next-generation flagship chassis?
There were already external references. The Ferrari Purosangue is equipped with a TASV ball screw solution, and Porsche launched the Porsche Active Ride distributed hydraulic solution. Top global OEMs are all deploying fully active suspensions.
Passive suspensions (such as coil springs) or semi-active suspensions (such as CDC) can only passively buffer when subjected to force, reducing road impacts, but cannot eliminate the motion tendency of the vehicle body. In contrast, fully active suspensions possess independent energy and drive units, which can actively apply thrust to the dampers, fundamentally intervening in vehicle body motion.
Since the fully active suspension is the key to fundamentally intervening in vehicle body motion, NIO listed the "SkyRide fully active suspension for mass production and delivery on the ET9 by the end of 2024" as the first item on the "Dare to Dream List." This list was full of goals that engineers considered "impossible."
They found ClearMotion, a chassis company headquartered in Massachusetts, USA, focusing on active suspensions, seeking deep joint R&D, with the goal directly targeting the integrated fully active hydraulic suspension.
At that time, the mainstream solution was the distributed hydraulic active suspension, which arranged the hydraulic pump and actuators separately, providing large torque and strong support, suitable for track scenarios, but with long oil circuits and large volumes, presenting a physical bottleneck in response speed. The integrated solution, however, directly integrates the controller, motor, and gear pump onto the damper, shortening the force transmission path to the minimum, with a response frequency of up to 40 Hz (adjusting 40 times per second). Due to system delay, distributed solutions or semi-active suspensions can mostly only handle 1-3 Hz long-wave undulations (such as the feeling of bouncing), while the range where the human body is most sensitive to vertical vibration is precisely 4-8 Hz—this is exactly the key frequency band that determines the "premium feel" of driving.
Considering comfort, NIO chose the integrated active suspension route. However, although the route was good, ClearMotion had no mass production experience.
To verify the feasibility of this system, NIO first modified an ES8 into an engineering verification vehicle, internally called the "Donkey Car," specifically born to verify the brand-new subsystem. This car ran very smoothly on the test tracks in Coventry, UK, but when shipped back to China and driven on complex domestic roads for the first time, it collapsed—the vibration filtering was even worse than that of ordinary cars.
Deeply frustrated, the team even felt that William Li would cut this project. But considering that only a system with a fast enough response like FAS (Fully Active Suspension) could hold the vehicle body steady and eliminate the feeling of weightlessness under China's complex road conditions—which is a direct killer of the premium feel—it was still worth a gamble.
So in the winter of 2022, two NIO engineers flew to Coventry, UK, with peripheral parts and control logic, staying in ClearMotion's office for a full month. Both sides re-sorted out the hydraulic matching logic, tuning the suspension that had been "spoiled" by European road conditions bit by bit to adapt to Chinese roads.
A month later, William Li personally test-drove the modified Donkey Car. After getting out of the car, the project was retained. But there was still a difficult problem: when outputting at full power, the instantaneous energy consumption of FAS was as high as several kilowatts, meaning a range loss of tens of kilometers, which was unacceptable to users.
To address this, NIO adopted a combination of "air spring + FAS" to support the vehicle body: letting the air spring do the "hard work"—maintaining the vehicle body height for a long time, locking the air without consuming power; while FAS only does the "quick work"—handling instantaneous bump adjustments. At the same time, the system also designed an energy micro-circulation. When the wheels are compressed, the FAS motor reversely recovers up to 5kW of energy, and the system temporarily stores this energy for the next use. Ultimately, the energy consumption was controlled at an extremely low level.
At NIO Day 2024, NIO showcased the strength of FAS through the famous "SkyRide Dance" of the ET9. When the ET9 carried a five-tier champagne tower over speed bumps without a ripple, and when the vehicle instantly lifted its body like a catapult launch in the face of a simulated rear-end collision, applause and cheers arose one after another.
Behind this was the extreme verification lasting three years by NIO's engineers.
04 The Chassis Evolves into an Intelligent System Integrating Software and Hardware
Unlike the approaches of other automakers and suppliers, NIO chose to develop layer by layer in-house from execution hardware (integrated fully active suspension, steer-by-wire, rear-wheel steering) to chassis control (ICC), vehicle motion control (VMC), and then to the global operating system (SkyOS). This is not five parallel modules, but a complete vertical technology stack from underlying hardware to top-level software.
Procuring a set of air springs or fully active suspensions independently is something many manufacturers can do. But if they simultaneously master the in-house development capabilities at four levels: underlying hardware, domain control, motion decision-making, and operating systems, and achieve cross-layer collaborative optimization, they can open up tuning spaces that are difficult to achieve through other paths—for example, the active suspension and electric drive torque responding collaboratively within the same control cycle, rather than two mutually independent "black-box" systems operating separately.
Behind this layout is NIO's long-term judgment on the electrification trend: the chassis will evolve from a purely mechanical system into an intelligent system integrating software and hardware. Building a complete vertical technology stack helps enhance product competitiveness and accumulate a certain technical threshold.
The VMC (Vehicle Motion Control platform) is the "commander" of this intelligent system. It connects upward to autonomous driving perception and downward to steering, braking, electric drive, and fully active suspension. If intelligent assisted driving had to call five or six controller interfaces for steering, braking, suspension, etc., respectively, it would be a disaster.
The "SkyRide Vision Motion" presented on the ET9 is exactly the result of the VMC coordinating the collaborative response between the fully active suspension, the cockpit domain, and the body domain, bringing the vehicle dynamics to this level.
NIO builds a "smart cerebellum" through the VMC and integrated fully active suspension, based on a consensus of the R&D team: the chassis should not be hardware locked at the factory; it should be a living entity that can grow and learn. The depth of this software definition is reflected in how the vehicle perceives the road surface: in the past, some luxury car brands in the industry attempted to achieve road surface preview through visual sensors, but single visual perception has certain limitations under low-light or severe weather conditions, and the control effect may be affected as a result.
In response, NIO launched 4D Comfort Navigation, identifying bumpy road sections through swarm intelligence; developed the ISS Comfort Stop algorithm, effectively alleviating the common phenomenon of front-end dive during EV braking. In addition, relying on the open architecture of the in-house chassis, it also pushed the EP Mode track mode via OTA, redesigned the relevant instrument interfaces, and supported users in making personalized adjustments to steering feel, driving dynamics, and cooling strategies.
This series of continuous iterations makes chassis tuning no longer limited to the factory state—users can continuously discover and adjust driving settings suitable for themselves as their usage habits deepen. This is the value of an in-house developed chassis.
In 2018, NIO was among the first to introduce the combination of air springs and CDC into high-end models of Chinese brands; in 2022, it mass-produced the in-house chassis domain controller ICC, initiating the exploration of chassis intelligence; in 2024, the SkyRide fully active chassis and steer-by-wire made their debut on the ET9, marking NIO's entry into a new stage of "fully active + fully by-wire";
Recently, the ES9 FAS version equipped with the SkyRide intelligent chassis was launched into the market, representing a comprehensive presentation of the technical accumulation of the NIO chassis team over the past eleven years.
A year later, the SkyRide intelligent chassis, verified by the ET9, has now become a very mature and reliable intelligent chassis system, presenting an industry-leading ride and driving experience on the ES9: the roll gradient of the NIO ES9 FAS version is reduced by 45% compared to the industry's executive flagship SUV level, comparable to the level of performance coupes; the acceleration pitch angle and braking pitch angle are reduced by 73% and 42% respectively compared to the industry's executive flagship SUV level, rivaling performance coupes, achieving stability with no front-end lift during acceleration and no front-end dive during braking; the high-frequency vibration filtering level is improved by 18.2% compared to the industry's executive flagship SUV level, jump pitch control is improved by 44.1%, and twisted road roll control is improved by 40.4%; it features high-precision preview of speed bumps, identifying the distance, width, and height of speed bumps at the centimeter level through assisted driving perception capabilities, achieving precise wheel lifting by the fully active suspension, and alleviating 48.1% of vertical impacts.
The world's first electro-hydraulic integrated fully active suspension equipped on the NIO ES9 FAS version can achieve four-wheel independent 6-DOF (Degrees of Freedom) vehicle body posture control, with a high-performance brushless motor making 1,000 torque adjustments per second, an actuator response frequency of up to 40 Hz, a vehicle body adjustment speed 60 times that of air springs, and can also achieve energy recovery with an instantaneous power of up to 5kW.
The continuous response frequency of the integrated fully active suspension is fast, more than 3 times that of the split type. Its action area can cover 1-10Hz road surface excitations, including vehicle body control for cornering roll and undulating pitch, as well as isolation and vibration filtering for speed bumps, patched roads, gravel roads, and washboard roads, especially capable of dissipating the 4-8Hz road surface vibrations to which the human body is most sensitive.
The goal of executive flagship SUVs is to achieve comfort and propriety in all scenarios, to simultaneously take into account posture control and vibration filtering, without swaying or bumping. Therefore, integrated fully active suspension technology has become one of the important technical directions for executive flagship SUVs.
In addition to the SkyRide intelligent chassis equipped with FAS, the ES9 gathers all of NIO's cutting-edge technological innovation achievements, such as the full-stack in-house developed smart lighting, which achieves technological breakthroughs in intelligent lighting through in-house controllers and three core algorithms; relying on the advantages of the native pure electric platform, it maximizes the space utilization of the passenger cabin and storage cabin; equipped with the industry's first 100% pure diamond tweeter and exclusive audio-visual technology, creating an acoustic experience comparable to top-tier concert halls; the ARNC advanced active noise cancellation system accurately captures noise through 28 high-precision sensing units, achieving millisecond-level noise cancellation, with peak noise reduction reaching 12 decibels...
This is in the same lineage as the "New Three Major Components" of intelligent vehicles proposed by William Li: intelligent driving chips, vehicle global operating system, and intelligent chassis. He believes that these three jointly determine the upper limit of experience and the upper limit of safety for intelligent vehicles.
In early 2026, NIO's first millionth mass-produced vehicle officially rolled off the assembly line. Looking back at the internal reflection on the "black box" issue in 2018, perhaps no one expected at that time that this inquiry would ultimately drive NIO onto a complete path of in-house chassis technology development.
05 Postscript
From the rollout of the first Jiefang truck in 1956 to today, China's automotive industry has walked for nearly 70 years.
The chassis, this inconspicuous field, was once the hardest high wall to climb. The mechanical experience, road spectrum data, and safety certifications accumulated over time each constituted a layer of technological blockade.
The electrification wave rewrote the rules of the game and also redefined the starting line. Software began to take over the vehicle body, suspension, and steering. Those control logic systems locked in black boxes by European Tier 1 suppliers for decades have been gradually unlocked by Chinese engineers.
From "Schrödinger's air suspension" to the "SkyRide Dance," Chinese automakers have used ten years to complete the position on the path of chassis intelligence that European Tier 1 suppliers took nearly half a century to reach. Behind this are automakers represented by "NIO," who have invested a large number of engineers in repeated debugging and waiting in front of the black box.
Today, the chassis is no longer just a bought black box. The definition right is returning bit by bit into the hands of Chinese engineers themselves. Over the past decade or more, the continuous investments in the chassis by automakers such as NIO, BYD, and Huawei have jointly raised the technical foundation of domestic intelligent vehicles.
Led by NIO, the SkyRide intelligent chassis is tearing open a gap from the software layer, breaking through the blockades and barriers of Western giants.
The breakthroughs are real, but the weaknesses are equally clear: brake-by-wire currently still relies on Bosch and Continental, and domestic substitution is still catching up; NVH (Noise, Vibration, and Harshness) is a systems engineering task, and decades of accumulation cannot be made up in a few years; the supply chain of some core sensors and actuators is still in the hands of foreign capital.
Single-point breakthroughs have occurred, but overall competitiveness remains to be made up.