Standard No.:	GB 20073-2025
English Name:	Performance and measurement method for braking of motorcycles and mopeds
Chinese Name:	摩托车和轻便摩托车制动性能要求及试验方法
Professional Classification:	GB    National Standard
Source Content Issued by:	SAMR, SAC
Issued on:	2025-12-31
Implemented on:	2027-7-1
Status:	valid
Superseding:	GB 20073-2018 Performance and measurement method for braking of motorcycles and mopeds
Target Language:	English
File Format:	PDF
Word Count:	21500 words
Translation Price(USD):	645.0
Delivery:	via email in 1~3 business day

ICS 43.140 CCS T 80 National Standard of the People’s Republic of China GB 20073-2025 Replaces GB 20073-2018 Performance and measurement method for braking of motorcycles and mopeds 摩托车和轻便摩托车制动性能要求及 试验方法 (English translation) Issue date: 2025-12-31 Implementation date: 2027-01-01 Issued by the State Administration for Market Regulation of the People's Republic of China the Standardization Administration of the People's Republic of China Contents Foreword III 1 Scope 1 2 Normative references 1 3 Terms and definitions 1 4 Requirements 4 5 Measurement methods 8 6 Same type judgment 9 7 Standard implementation 11 Annex A (Normative) Measurement and performance for service brake system 12 Annex B (Normative) Measurement and performance for antilock brake system 22 Annex C (Normative) Partial failure measurement and performance for split service brake system 26 Annex D (Normative) Failure measurement and performance for power-assisted braking system 27 Annex E (Normative) Failure measurement and performance for combined brake system 28 Annex F (Normative) Failure measurement and performance for complex electronic vehicle control systems 29 Annex G (Normative) Determination of the peak brake force coefficient 31 Bibliography 34 Performance and measurement method for braking of motorcycles and mopeds 1 Scope This document specifies the performance and measurement method, same type judgment and standard implementation for braking of motorcycles and mopeds. This part is applicable to motorcycles and mopeds. This standard is not applicable to vehicles for the disabled and off-road motorcycles. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies. GB/T 5359.1 Term for motorcycles and mopeds - Part 1: Types of vehicles GB/T 5359.4 Term for motorcycles and mopeds - Part 4: Mass of vehicle with two and three wheels GB 15365 Symbols for controls, indicators and tell tales for motorcycles and mopeds GB/T 20076-2021 Measurement methods of maximum torque and maximum net power of engines for motorcycles and mopeds GB 34660 Road vehicles - Requirements and test methods of electromagnetic compatibility 3 Terms and definitions For the purposes of this document, the terms and definitions given in GB/T 5359.1 and GB/T 5359.4, as well as the following apply. 3.1 brake system combination of components that gradually decelerates or stops a moving vehicle, or maintains a stationary vehicle stopped Note: A brake system consists of a control, a transmission and a brake mechanism, and does not include the engine. 3.2 control part actuated directly by the rider in order to supply or control the energy required for braking the vehicle to the transmission 3.3 transmission combination of components located between the control and the brake, enabling functional connection between them 3.4 brake part in the brake system that generates the force to oppose the vehicle's movement 3.5 service brake system brake system that decelerates a moving vehicle 3.6 single brake system service brake system which acts on only one axle 3.7 combined brake system, CBS service brake system that operates single controls to control brakes on different wheels jointly Note: For two-wheeled mopeds (Category L1) and two-wheeled motorcycles (Category L3), it operates single controls to control at least two brakes on different wheels jointly; for three-wheeled mopeds (Category L2) and right three-wheeled motorcycles (Category L5), it operates single controls to control brakes on all wheels jointly ; for motorcycles with sidecar (Category L4), it operates single controls to control at least the brakes on the front wheel and the rear wheel, and it shall be considered one rear brake when the rear wheel and sidecar wheel are controlled at the same time. 3.8 secondary brake system second service brake system on a vehicle equipped with a combined brake system 3.9 split service brake system, SSBS brake system that controls brakes on all wheels, in which two or more subsystems are controlled by two or more subsystems The failure of any single subsystem shall not affect the functionality of the other subsystems. Note: Such as system failure caused by hydraulic line leakage. 3.10 power-assisted braking system braking system in which one or more energy supply devices assist the driver's physical effort to apply braking force Note: Such as vacuum-assisted braking system (with a vacuum booster). 3.11 antilock brake system; ABS system capable of identifying the degree of wheel slip relative to the ground and automatically adjusting the braking force on the wheels to limit the wheel slip relative to the ground 3.12 wheellock state when the wheel slip ratio is 1.00 3.13 actuate activation and release of the control device 3.14 braking signal logic signal indicating activation of the brake light 3.15 electric regenerative braking system braking system that converts the kinetic energy of a vehicle into electrical energy during deceleration Note: This system is not part of the service brake system. 3.16 peak braking coefficient; PBC coefficient of friction between tire and road surface, measured based on the maximum deceleration of a rolling tire 3.17 maximum speed vmax speed at which the motorcycle covers a specified distance in the shortest time under the specified test conditions and methods Note: For the test conditions and methods, see GB/T 5378. 3.18 engine disconnected disconnection of the engine from the drive wheels 3.19 initial brake temperature temperature of the brake before any braking action is applied Note: If multiple brakes are controlled simultaneously, the temperature of the brake with the highest temperature shall be selected. 3.20 laden condition in which the vehicle is loaded to the maximum design total mass 3.21 lightly loaded total mass of the vehicle plus the driver's mass (75 kg) and the test equipment mass (15 kg), or the laden mass, whichever is less Note: In the case of ABS tests on a low friction surface, the mass of test equipment (including protective supports) is 30 kg. 3.22 test speed vehicle speed at the moment the driver begins to operate the control during the test Note: If the test requires simultaneous operation of two controls, the moment when the first control begins to be operated shall be considered as the start of control device operation. 3.23 stopping distance distance traveled by the vehicle from the moment the driver begins to operate the control until the vehicle completely stops Note: If the test requires simultaneous operation of two controls, the moment when the first control begins to be operated shall be considered as the start of control device operation. 3.24 baseline test one or more braking tests conducted prior to the thermal fade procedure or wet test to evaluate braking performance 3.25 fully cycling process in which the antilock brake system repeatedly or continuously adjusts the braking force to prevent lock of directly controlled wheels 3.26 automatically commanded braking function of an integrated electronic vehicle control system that automatically assesses onboard trigger information and operates the braking system or the brakes on a specific axle to decelerate the vehicle 3.27 safety concept measures taken to the system integrity in the design of a system (e.g., an electrical unit) to ensure safe operation even in the event of circuit failure Note: maintaining partial works or providing backup systems for critical vehicle functions falls within the scope of safety concept. 3.28 electronic control system combination of units that collaborate through electronic data processing to achieve predetermined vehicle control functions Note: This electronic control system is typically software-controlled, consisting of independent functional components such as sensors, electronic control units (ECU) and actuators, connected by transmission devices. The system may include mechanical, electro-pneumatic, and electro-hydraulic components. 3.29 complex electronic vehicle control systems electronic control system that adheres to the control hierarchy that upper-level electronic control systems/functions can override lower-level ones The controlled functions become part of the complex system. 3.30 units smallest part of an electronic control system Note: The combination of these components can be identified, analyzed or replaced as a single entity. 4 Requirements 4.1 Basic requirements The vehicle shall meet the test requirements specified for its vehicle type and brake system characteristics. For right three-wheeled mopeds and right three-wheeled motorcycles with two wheels installed on the same axle and a track width not exceeding 460 mm, they shall respectively meet the brake system function, characteristics and performance requirements applicable to two-wheeled mopeds and two-wheeled motorcycles. 4.2 Brake system function 4.2.1 Service brake system It shall allow the driver, while in the normal driving position, to operate the control of the service brake system without removing both hands from the handlebar or steering wheel. 4.2.2 Secondary brake system (if any) It shall allow the driver, while in the normal driving position, to operate the control of the emergency braking system with at least one hand holding the handlebar or steering wheel. 4.2.3 Parking brake system (if any) 4.2.3.1 If the vehicle is equipped with a parking brake system, the system shall be able to keep the vehicle stationary on the test slope described in 5.1.1.3. 4.2.3.2 Parking brake system shall a) comprise a control which is isolated from the service brake system control; b) lock the working parts only in a purely mechanical manner. 4.2.3.3 The parking brake system shall allow the driver, while in the normal driving position, to operate the control of the parking brake system. 4.2.3.4 The parking brake system fitted to three-wheeled mopeds (Category L2), motorcycles with sidecar (Category L4) and right three-wheeled motorcycles (Category L5) shall meet the requirements of A.3.5 in Annex A. 4.3 Characteristics of brake system 4.3.1 Two-wheeled mopeds (Category L1) and two-wheeled motorcycles (Category L3) Two-wheeled mopeds (Category L1) and motorcycles (Category L3) shall be fitted with two single service brake systems or a split service brake system, with at least one brake controlling the front wheel and the other controlling the rear wheel. 4.3.2 Motorcycle with sidecar (Category L4) 4.3.3 Motorcycles with sidecar (Category L4) shall meet the requirements of 4.3.1. If the vehicle can meet the performance requirements specified in Annexes A - E, brake is not required for the sidecar.

Contents Foreword III 1 Scope 2 Normative references 3 Terms and definitions 4 Requirements 5 Measurement methods 6 Same type judgment 7 Standard implementation Annex A (Normative) Measurement and performance for service brake system Annex B (Normative) Measurement and performance for antilock brake system Annex C (Normative) Partial failure measurement and performance for split service brake system Annex D (Normative) Failure measurement and performance for power-assisted braking system Annex E (Normative) Failure measurement and performance for combined brake system Annex F (Normative) Failure measurement and performance for complex electronic vehicle control systems Annex G (Normative) Determination of the peak brake force coefficient Bibliography