The locking force standard of adjustable dumbbells: a key consideration for wholesale buyers

The locking force standard of Adjustable Dumbbells: a key consideration for wholesale buyers
In today's global fitness equipment market, adjustable dumbbells are widely favored by fitness enthusiasts and professional bodybuilders for their convenience and versatility. For international wholesale buyers, it is crucial to choose adjustable dumbbells with reliable quality and excellent performance, because it is directly related to the market competitiveness of the product and customer satisfaction. The locking force standard of adjustable dumbbells is one of the core elements for evaluating their quality and performance.

I. Introduction
With the continuous improvement of people's health awareness, the home fitness equipment market is booming. As an efficient and flexible strength training tool, adjustable dumbbells meet the needs of different users for strength training. Its unique design allows users to quickly adjust the weight of the dumbbells through simple operations, thereby achieving a variety of training goals. However, among many brands of adjustable dumbbells, how to ensure that their locking force can meet the safety and stability requirements of high-intensity training has become a common focus of wholesale buyers and consumers.

2. The importance of the locking force standard of adjustable dumbbells
(I) Safety guarantee
During strength training, users will exert greater force on the dumbbells. If the locking force of the adjustable dumbbell is insufficient, the plates may become loose or even fall off during training, which will bring serious safety hazards to users, such as injuring hands and feet, spraining joints, etc. For wholesale buyers, selling products with safety risks will not only damage the brand image, but also face a large number of after-sales claims and legal disputes. Therefore, ensuring that the purchased adjustable dumbbells have a locking force that meets the standard is the key to protecting user safety and corporate reputation.
(II) Reflection of product performance and quality
The locking force standard directly reflects the performance and quality level of the adjustable dumbbell. High-quality adjustable dumbbells can maintain a stable locking force under different weight adjustment states, ensuring that users can obtain accurate weight feedback and good training effects when performing strength training. For example, when users perform high-weight squats or bench presses, the dumbbell plates must be firmly fixed to the handles without any looseness or shaking. This not only helps users improve training efficiency, but also enhances their trust and satisfaction with the product.
(III) Extending product life
A locking force that meets the standard can effectively reduce friction and wear between the plates and the handles. During long-term use, if the locking force is unstable or too small, the relative movement between the weight plate and the handle will intensify, resulting in damage to components and shortened product life. A reliable locking force design can make the components fit closely, reduce the additional stress caused by looseness, and thus extend the overall service life of the adjustable dumbbell, providing users with a more cost-effective choice.

3. Interpretation of the current adjustable dumbbell locking force standards
(I) International standards
Globally, many international organizations and institutions have established relevant standards for the safety and performance of fitness equipment. For example, the European EN 957 standard specifies in detail the requirements and test methods for commercial fitness equipment, including the requirements for the locking force of adjustable dumbbells. According to the EN 957 standard, the locking device of the adjustable dumbbell should be able to remain stable under the specified maximum weight, and after a certain number of locking and unlocking operations, it can still ensure that the weight plate will not loosen or fall off. In addition, the US ASTM F2040 standard also regulates home fitness equipment and clearly explains the locking force test method and safety requirements for adjustable dumbbells. These international standards provide unified specifications and guidelines for the production and sale of adjustable dumbbells, which helps to improve the safety and reliability of products.
(II) National standards
Many countries have also formulated their own national standards for fitness equipment to ensure product quality and consumer safety in the domestic market. Taking China as an example, the new regulations T/CASME 946-2023 and GB 17498-2008 in 2025 have updated and refined the locking force test methods and requirements for adjustable dumbbells. Among them, the new standard stipulates that after the 25kg bell plate is fixed vertically, the displacement judgment standard is changed from qualitative observation to quantitative measurement, requiring the displacement of the locker within a 3-minute test cycle to be < 3mm, which is 67% higher than the original standard. The implementation of this standard makes the locking force test of adjustable dumbbells more scientific and rigorous, and provides a clearer basis for the production of domestic enterprises and the selection of purchasers.
(III) Industry standards
In addition to international and national standards, some industry associations will also formulate corresponding standards to regulate the development of the industry. For example, organizations such as the International Human Resources Association (IHRSA) will publish recommended standards for performance indicators such as the locking force of adjustable dumbbells based on industry development trends and actual conditions. These industry standards usually combine the company's production experience and market feedback to put forward more specific and detailed requirements for the safety and reliability of the product, providing a more comprehensive reference for wholesale buyers.

4. Factors affecting the locking force of adjustable dumbbells
(I) Design and quality of the locking device
The locking device is one of the core components of the adjustable dumbbell, and its design and quality directly determine the locking force of the dumbbell. Common locking devices include knob type, lever type, button type and other types. Different types of locking devices differ in structural principles and operating methods, so their locking force performance will also be different. For example, the knob-type locking device usually controls the extension and retraction of the locking screw by rotating the knob to fix the bell plate. If the torque design of the knob is unreasonable or the material of the locking screw is poor, problems such as screw deformation and knob loosening may occur during long-term use, resulting in a decrease in locking force. High-quality locking devices are made of advanced design concepts and high-quality materials, which can ensure stable and reliable locking force in various use environments.
(II) The matching accuracy of the bell plate and the handle
The matching accuracy between the bell plate and the handle is also an important factor affecting the locking force. In adjustable dumbbells, the bell plate needs to be accurately installed on the guide rail or slot of the handle to ensure that the locking device can effectively fix the bell plate. If there is a gap or excessive interference between the bell plate and the handle, it will increase the burden of the locking device and affect the transmission and stability of the locking force. In addition, the shape, size and material of the bell plate will also affect its matching effect with the handle. For example, the use of high-quality metal bell plates has higher dimensional accuracy and surface finish, and the match with the handle is tighter, which helps to improve the locking force.
(III) Material selection and quality
Material is the basis for determining the locking force of adjustable dumbbells. The materials used for components such as the handle, locking device and bell plate need to have sufficient strength, hardness and wear resistance to withstand the various stresses and friction generated during training. Generally speaking, the handles of adjustable dumbbells are usually made of metal materials such as steel or aluminum alloy, which have high strength and stability and can provide good support for the locking device. However, if the quality of the material does not meet the requirements, such as insufficient strength of steel and insufficient hardness of aluminum alloy, it may cause problems such as deformation of the handle and damage to the locking device, thereby affecting the locking force. In addition, the quality of the bell material will also affect the locking force. For example, the use of low-quality plastic bells may deform or break during training, and cannot fit tightly with the locking device, reducing the locking force.

5 Use environment and maintenance
The use environment and maintenance of adjustable dumbbells will also have a certain impact on their locking force. When used in harsh environments such as high temperature, humidity, and dust, the locking device is prone to corrosion, wear, and blockage, resulting in a decrease in locking force. For example, when using dumbbells near the seaside or swimming pool, the salt and humidity in the air will corrode the metal parts, causing the locking screw to rust and get stuck, affecting its normal operation. In addition, if the user does not pay attention to maintenance during use, such as not cleaning the dust and dirt on the weight plate and handle in time, and not checking the wear of the locking device regularly, it will also accelerate the aging and damage of the parts and reduce the locking force.
V. How to test the locking force of adjustable dumbbells
(I) Conventional test methods
According to relevant standards and specifications, the locking force test of adjustable dumbbells usually adopts the following methods:
Static tension test: Fix the handle of the adjustable dumbbell on the test equipment, and then apply a certain static tension on the weight plate to simulate the user's pulling action on the dumbbell during training. By measuring the displacement of the locking device under this tension or whether it is loose or falling off, it is evaluated whether its locking force meets the standard requirements. In general, the test tension will be set according to the maximum weight and usage scenario of the dumbbell. For example, for commercial-grade adjustable dumbbells, the test tension may reach hundreds of kilograms.
Dynamic fatigue test: Considering that the adjustable dumbbell will undergo a large number of locking and unlocking operations during actual use, dynamic fatigue testing is required. During the test, the adjustable dumbbells are repeatedly locked and unlocked to simulate long-term use by users. After a certain number of cyclic tests, the wear, deformation and damage of the locking device, bell plates and handles are checked, as well as whether the locking force can still be maintained within the specified range. Usually, the number of cycles of dynamic fatigue testing is determined according to the expected service life and quality grade of the product, generally ranging from thousands to tens of thousands of times.
Displacement measurement method: This is a more accurate locking force test method, especially in the new 2025 regulations. Assemble the adjustable dumbbells according to the specified weight configuration, and fix the bell plates vertically on the test device. During the 3-minute test cycle, the displacement of the lock is measured by a high-precision displacement sensor. If the displacement is less than the specified value (such as 3mm), it means that the locking force meets the standard requirements. This method can quantitatively evaluate the stability of the locking force, avoid interference from human factors, and improve the accuracy and reliability of the test results.
(II) On-site rapid testing methods
For wholesale buyers, it is impossible to conduct comprehensive laboratory tests on every batch of adjustable dumbbells during the actual purchasing process. Therefore, it is very necessary to master some on-site rapid testing methods:
Manual inspection method: Purchasers can preliminarily check the locking force of adjustable dumbbells through manual operation. First, adjust the dumbbells to different weight levels, and then shake the weight plate vigorously to feel whether it is loose. At the same time, check the smoothness and stability of the locking device during operation, and whether there are problems such as jamming and slipping teeth. In addition, you can also try to rotate the weight plate to check whether it fits tightly with the handle. Although this method cannot accurately measure the specific value of the locking force, it can quickly discover some obvious quality problems, such as serious lack of locking force and loose weight plates.
Visual inspection method: By visually inspecting the appearance and structure of the adjustable dumbbell, some potential problems that may affect the locking force can be found. For example, check whether the parts of the locking device are damaged, deformed or missing; whether the surface of the weight plate is flat, cracked or notched; whether the guide rail or slot of the handle is intact, etc. If these parts are found to have obvious defects, the locking force of the adjustable dumbbell is likely to not meet the standard requirements, and further detailed inspection or purchase is required.

6. Suggestions for purchasing adjustable dumbbells that meet the locking force standards
(I) Select reliable suppliers
Choosing suppliers with good reputation and quality assurance capabilities is the basis for purchasing adjustable dumbbells that meet the locking force standards. When selecting suppliers, wholesale buyers can consider the following aspects:
Qualifications and certifications of suppliers: Check whether the supplier has relevant qualification certificates and product certifications, such as ISO 9001 quality management system certification, CE certification, GS certification, etc. These certifications indicate that the supplier meets certain international standards in production management and product quality control, and its products are more likely to meet performance requirements such as locking force.
Production experience and reputation of suppliers: Understand the supplier's years of experience in the field of adjustable dumbbell production and market reputation. Suppliers with rich production experience are usually more mature in product design, manufacturing process and quality control, and can better guarantee the locking force performance of the product. In addition, by consulting other peer buyers or customers about the supplier's product quality and service, you can get some intuitive evaluations and suggestions to help you choose a reputable supplier.
Supplier's quality control system: Investigate whether the supplier has established a complete quality control system, and whether there are strict quality inspection processes and standards in all links from raw material procurement, parts processing to product assembly and factory inspection. Require suppliers to provide detailed production process documents and quality inspection reports to understand their control measures and test methods for key performance indicators such as locking force. Choosing suppliers that focus on quality control and have strict inspection processes can effectively reduce the risk of purchasing substandard products.
(II) Strict product inspection and acceptance
During the procurement process, wholesale buyers should negotiate with suppliers to formulate strict product inspection and acceptance standards to ensure that the purchased adjustable dumbbells meet the locking force standard requirements. Product inspection can be divided into the following stages:
Raw material inspection: Require suppliers to provide quality certification documents for raw materials and conduct sampling inspections on raw materials before production. Check whether the material, specifications and performance of the raw materials meet the product design requirements, and ensure that the raw material quality of key components such as locking devices, handles and bell plates is reliable.
Inspection during the production process: During the supplier's production process, the purchaser can arrange for technicians or third-party testing agencies to conduct regular inspections. Focus on checking whether the production process is carried out in accordance with the prescribed standards, whether the processing accuracy and assembly quality of the parts meet the requirements, and whether the debugging and testing of the locking device are qualified. Through inspections during the production process, quality problems that may arise in the production process can be discovered and solved in a timely manner to avoid mass production of products that do not meet the standards.
Finished product acceptance inspection: After the product is produced, the purchaser should strictly inspect the finished product in accordance with the agreed acceptance standards. The inspection content should include various aspects such as appearance inspection, weight deviation detection, and locking force test. For the locking force test, the conventional test method mentioned above or the on-site rapid detection method can be used, and the test can be carried out according to a certain sampling ratio. Only adjustable dumbbells that have been strictly inspected and meet the locking force standards can be accepted and put into storage.
(III) Establish a long-term cooperative relationship and quality feedback mechanism
In order to ensure the long-term and stable procurement of adjustable dumbbells that meet the locking force standards, wholesale purchasers should establish a long-term cooperative relationship with suppliers and establish an effective quality feedback mechanism. During the cooperation process, the purchaser should promptly feedback the quality problems that occur during the market sales and customer use of the product to the supplier, jointly analyze the causes and take improvement measures. Through close cooperation and continuous communication with suppliers, suppliers are encouraged to continuously optimize product quality and improve the stability and reliability of performance indicators such as locking force. At the same time, long-term cooperative relationships also help purchasers obtain more favorable conditions in terms of procurement costs, delivery time, etc., and achieve mutual benefit and win-win results for both parties.

7. Development trend and future prospects of adjustable dumbbell locking force standards
With the continuous advancement of science and technology and the increasing diversification of people's fitness needs, the adjustable dumbbell locking force standards are also constantly developing and improving. In the future, the adjustable dumbbell locking force standards may show the following developments Development trend:
(i) Higher precision requirements
In order to meet the requirements of professional fitness people and high-end fitness market for strength training accuracy, the locking force standard will further improve the requirements for adjustable dumbbell accuracy. For example, the allowable error range of the locking force may be further reduced, and the displacement limit may be more stringent. This will prompt manufacturers to adopt more advanced manufacturing processes and testing technologies, improve product quality and performance, and ensure that accurate and stable locking forces can be provided under different weight adjustment conditions.
(ii) Intelligent and automated testing methods
With the continuous development of intelligent sensor technology and automated testing technology, the test method for the locking force of adjustable dumbbells will be more intelligent and automated. Future testing equipment may have the functions of automatically identifying Dumbbell Weights, automatically applying and adjusting test loads, real-time monitoring of locking force changes, and data recording and analysis. This can not only improve test efficiency and accuracy, but also reduce the impact of human factors on test results, and provide more reliable and convenient testing tools for wholesale buyers and quality inspection agencies.
(iii) Combined with environmental protection and sustainable development requirements
Against the background of increasing global environmental awareness, the locking force standard of adjustable dumbbells may be combined with environmental protection and sustainable development requirements. For example, in the design and material selection of the locking device, more attention will be paid to the use of environmentally friendly and recyclable materials to reduce pollution to the environment. At the same time, the standard may put forward higher requirements for the service life and maintainability of the product to promote the recycling of resources and reduce the generation of waste.
(IV) Deep integration with ergonomics and user experience
As people pay more attention to the ergonomics and user experience of fitness equipment, the adjustable dumbbell locking force standard will also pay more attention to the deep integration with ergonomics and user experience. Future standards may put forward specific requirements for the convenience and comfort of the locking device to ensure that users can adjust the weight of the dumbbell more easily and smoothly, while avoiding the impact of improper operation on the locking force. In addition, the standard may also consider the user experience of dumbbells in different usage scenarios, such as home fitness, commercial gyms, outdoor fitness, etc., to formulate more targeted locking force requirements and test methods.

8. Conclusion
The locking force standard of adjustable dumbbells is a key indicator for evaluating product quality and performance, which is of great significance to international wholesale buyers. It is directly related to the safety of users, the market competitiveness of products and the brand image of enterprises. By gaining an in-depth understanding of the connotation, influencing factors, test methods, and purchasing recommendations of the locking force standard, wholesale buyers can more scientifically and accurately select adjustable dumbbell products that meet the standards, meet market demand, and achieve commercial success.
In the future development, with the advancement of technology and changes in the market, the locking force standard of adjustable dumbbells will continue to innovate and improve. Wholesale buyers should pay close attention to these development trends, maintain close cooperation with suppliers, actively participate in the formulation and promotion of industry standards, and jointly promote the healthy development of the adjustable dumbbell industry, providing better quality and safer products for global fitness enthusiasts.