Cause Of Broken Tire Screws

The function of the tire screw is to fasten the wheel hub and wheel together. Normally, screws only bear axial tension, not radial shear stress. When the hub nut is loose, the force of the screw changes from tensile to shear stress. When the sudden increase in load exceeds its rated load, the screw will be shear and break. Once the screw breaks, it can be very dangerous for the car. Based on the knowledge of fastener screws, Xinchi Fastener Company shares the causes of loosening and breakage of screws and effective preventive measures in addition to the quality and processing reasons of screws and nuts.

1. The screws are not tightened according to technical requirements during installation. Or the tightness gap between the nuts is large. Once some nuts are loose, the load of other nuts will increase greatly.
2. In the maintenance and installation of tires, many people use general wind cannon disassembly and installation, rather than fixed torsion wind cannon installation, so there is often no control of the upper limit of torque when installing. Sometimes the repairman may increase the tightening torque because he is worried that the tire screws are not tightened, so that the tightening torque of the normal 550~650Nm(general bus) can be increased to 100ONm or even larger, and the tire screws are stretched in frequent tire disassembly and assembly to loosen the tire nuts.
3. The screw hole of the tire ring is worn or deformed, and the nut torque meets the requirement, but the tire ring is not pressed tightly enough.
4. When the screw thread of the bolt and nut is damaged after long-term use, the disk spring washer fails, or the flat washer is cracked and deformed, the nut can not play a good locking function, and thus the nut is loose.
5. The locating ring of the hub nut is damaged or missing, or the inner hole of the steel ring is out of round due to the extrusion deformation of the screw hole. Because of the simplified operation of installing the tire, the hub nuts are not tightened diagonally, but in place at once, one at a time. For bolts without center positioning sleeves, this method of operation will cause the bolt to deviate from center positioning. The nut has been tightened during assembly, but because of the asymmetric arrangement of bolts and screw holes, the rotation radius of the tire is not equal. That way, the wheel won’t turn long before the nut loosens.
6. Frequently used but infrequently maintained. Drivers and repairmen do not have a strong sense of responsibility for their work. They do not check regularly according to the standard requirements. Some of them do check but are not serious.

Xinchi Fastener Company is a trustworthy fastener company, especially in furniture nuts. And we are the designated fastener supplier to“STAPLE”. As a trusted fastener supplier,  Xinchi Fastener Company can offer a wide range of high-quality fasteners, including tee nuts, screws, bolts, rivets, washers, etc. If you want to know more about fasteners or want to wholesale fasteners, please feel free to contact us. And then our experienced and expert service team will reply to you as soon as possible.