How to find a good running belt for your treadmill?
By Roger Yao
The running belt is an important component for a treadmill that provides the user with a contact surface and support friction during running. Choosing a suitable running belt is critical for the stable operation of the treadmill and make sure a comfortable and safe running experience.
1. Comments problems of running belt
Running belt is the part that is prone to wear and tear after certain use. According to our experience, quality complaints about running belts account for a considerable part in treadmill after-sales services. And most consumers often cannot solve the quality problems related to running belts by themselves. They may need professional guidance and replacement services from after-sales service personnel.
The following are common quality problems for running belt:
1.1 Abrasion
The wear position of the running belt is usually on the inner side of the running belt, that is, the warp and weft layers start to detach and wear out, which may eventually lead to the breakage and failure of the running belt. It is reflected in the market that the average service life of the running belt of a household treadmill is about 300 hours. Unfortunately, there is no authoritative statistics to know how long or how many kilometers the life time of a running belt of a certain specification is.
1.2 Abnormal sound
Due to the poor handling of the interface, it will collide with the roller during operation and the product will make a rhythmic "boom, boom, boom" abnormal sound.
1.3 Slipping
Insufficient tension of the running belt, or excessive lubrication, will cause slipping. The slipping g phenomenon is more obvious for heavy users or when stepping on the running belt quickly.
1.4 Deviation
Usually, the running belt is tilted to one side, which may rub against the side bars or meander during running.
1.5 Wrinkling
After a period of time, some users may find that the middle of the running belt was wrinkled, which made it impossible to continue using it.
1.6 Static electricity
Running belts with poor antistatic properties may accumulate static high voltage during operation, and the discharge of static electricity may damage the controller and circuit board of the treadmill, resulting in failure of the whole machine.
2. Know-how of running belt
2.1 Different types of running belts
The thickness of the running belt of the home-use treadmill is mostly from 1.4MM to 2.0MM, and the structure of single cloth double glue or double cloth double glue is usually used.
The thickness of the running belt of light commercial treadmills and commercial treadmills is mostly 2.0MM~4.5MM. If the commercial treadmill is made of PU material, most of them are 1.8MM thick.
The structure of the running belt is usually distinguished by several layers of cloth and several layers of glue.
According to the expert and also the owner of Xinnuoxing belt company, Mr. Lin Jiuqing, the running belt with a thickness of 1.4-1.5MM adopts single cloth double glue; the running belt with a thickness of 1.6MM-1.8MM adopts both single cloth double glue and double cloth double glue; the running belt with a thickness above 2.0 uses double cloth double glue; For running belts with a thickness of more than 4.5MM, it may be necessary to use three cloths and three glues.
2.2 Three production processes for running belt
laminating process, coating and scraping process, and pressing process
Laminating process
the running belt cloth and the PVC coil arelaminated together at 120 degrees to make the running belt master coil.
Advantages: low cost of production equipment, high production efficiency, and low overall cost; Disadvantages: the peeling force will be poor, and it may delaminate after a long time of use;
Coating and scraping process
Scrape PVC resin at temperature 180 degrees on the running belt cloth to make it into the running belt master coil.
Advantages: good peeling force, low cost of production equipment, easy to adjust when changing colors; Disadvantages: low production efficiency, and may crack after long-term use.
Pressing process
After extruding PVC resin, it is melted with the running belt cloth at 180 degrees after multi-roller pressing, and made into the running belt master coil.
Advantages: good peeling force, high production efficiency, product life is more than 30% better;Disadvantages: the cost of production equipment is 4 times higher.
2.3 The material composition
The structure of the running belt is divided into base cloth plus PVC rubber or PU rubber. The base fabric material is PET plus PET monofilament (the soft cloth part has no PET monofilament); the main material of the PVC glue formula is: PVC and plasticizer (DOP can only pass ROHS, DINP or DOTP can pass REACH)
3. Selection principle of running belt
3.1 Length, width and thickness specifications
The length and width specifications of the running belt are usually determined by the structure of the treadmill. The provisions of the European EN957-6 standard have made clear regulations (see the figure below). For example, for a class B treadmill, the width of the running belt should be greater than 400mm; if the maximum speed reaches 16KM/H, the effective length of the running belt should be greater than 1300mm.
As for the thickness, home use treadmills usually range from 1.4mm to 1.8mm, while commercial treadmills use thicker (2~3mm) specifications. Generally speaking, the user experience of a thicker running belt is much better than a thinner one.
But, it does not mean that the thicker the running belt, the better. If supplier places too much emphasis on soft comfort and uses an extra-thick running belt, the motor may be overloaded due to insufficient horsepower and improper matching with the rollers, which will shorten the service life.
3.2 Running belt texture
the surface texture for the belt is also a key consideration.
The current mainstream running belt patterns are: grass pattern, diamond pattern, golf pattern, tire pattern (also called cross pattern), and Siegling's CS pattern (thinner than grass pattern). The coefficient of friction of these textures can reach international or domestic standards. Customers can choose according to the customers’ preferences in their local market. In addition, the grass pattern is more convenient for cleaning and maintenance. Most of the commercial treadmills of well-known brands in the world use shallow textures such as CS patterns that are easier to clean.
3.3 Matching of running belt and roller
The thickness of the running belt should match the diameter of the rollers, improper matching will result in shortened running belt life time and do harm to normal operation of the treadmill power system.
The common practice in the market : Try to use a running belt with a thickness of less than 1.6MM for the Φ38 roller, and the width should not exceed 400MM. For a 2.0MM thick running belt, to use on the rollers larger than Φ46. And 2.5MM thick running belt, better to use rollers larger than Φ55;
4. Running belt performance index
4.1 Extensibility
Usually, manufacturers use static pressure test or the method of measuring the length of the running belt before and after the actual running of the treadmill to evaluate. The running belt of mechanical running or the running belt of 10KM/H and below electric treadmill should be less than 10‰ stretch rate; the running belt of 12KM/H and above electric treadmill should be less than 8‰ stretch rate.
4.2 Belt tensile strength
Test on thickness of 1.4mm: withstand > 180kgf on main body and >100kgf on joint
Test on thickness of 1.6mm: withstand > 200kgf on main body and >110kgf on joint
Test on thickness of 1.8mm: withstand > 250kgf on main body and >140kgf on joint
Test on thickness of more than 2.0mm: withstand > 280kgf on main body and >180kgf on joint
4.3 Static electricity on the bottom material
Photo：static elecric tester
Use a multimeter to test the resistance value of the static yarn at the bottom of the running belt at a distance of 1cm. Some large brands require that the resistance value should be 70KΩ~170KΩ. When testing the highest speed with an electrostatic meter, the static voltage in the middle of the running belt should be less than 2KV.
*Note: The above are the reference criteria from some running belt manufacturers.
In the practice, In order to ensure the stability and reliability of the running belt quality, treadmill suppliers may pick certain samples for durability testing or called life test. Usually, the factory's running belt durability test is included in the type test plan of the whole machine, and it is also recommended that do incoming test before assembly production of treadmill, which uses customized equipment for special testing, that is, to apply sufficient tension on the running belt. The upper motor and the corresponding roller are tested for a long period of service life.
5. Adjustment & maintenance
On the assembly line of the treadmill factory, workers will perform the actions of adjusting the center of the running belt, controlling the proper tension, and lubricating with silicone oil. However, due to omissions or irregular operating procedures, the running belt was not properly adjusted before leaving the factory, which will bring potential hidden danger to consumer's use.
Photo: use Allen Key to adjust the tension and centralization.
If user finds that the running belt deviates or slips, they should adjust it in time according to the instructions in the manual. If the running belt makes an abnormally dry friction sound, check the lubrication between the inside of the running belt and the running deck, and consider adding silicone oil.
Photo: Silicon oil bottle
Recent years, some treadmills are designed with an automatic refueling system to make the refueling process easier and more convenient. But the more silicone oil is not always the better, too much silicone oil will cause the running belt to slip. Usually, the dosage of silicone oil is 20ml/M2 each time, the actual dosage should consider the actual situation of running board and the frequency of lubrication in the past.
6. Outlook of treadmill running belt
Smoother and more beautiful joint technology.
The softer and more elastic running belt improves the cushioning and comfort of the running platform.
Development and use of refueling-free running belt. This design can avoid the pain point of users forgetting to add silicone oil or not knowing the frequency and dosage of silicone oil.
More and more commercial treadmills use PU running belts. It is characterized by longer service life and better extensibility. Reduces frequency of belt changes and roller adjustments. Not only does it save costs, but the application of PU material is also more environmentally friendly.
For more questions about running belt, please contact us at cs01@fitqs.com