Thread mismatch between the wheel bolt and the wheel nut: This situation is relatively rare, as most workers will not directly fit the nut onto the pneumatic wrench socket and press it against the bolt for installation.

Improper installation by operators: For ordinary wheel nuts during maintenance, the most common issue is that maintenance workers screw the nut onto the bolt by 2-3 threads and then directly tighten it with a pneumatic wrench. The vibration of the pneumatic wrench during installation is prone to causing force deviation, which easily leads to nut thread stripping. Ensure the nut is screwed onto the bolt by at least 5 threads. When using socket nuts, manually screw them in to ensure the socket is fully inserted into the wheel bolt hole before using mechanical installation tools.

Abnormal damage to the threads on the wheel bolt: During daily removal or installation of wheel bolts, the threads on the bolts are often damaged. Such abnormal damage to the bolt threads can easily result in excessive friction coefficient, damage, or direct deformation of the wheel nut threads, ultimately leading to nut thread stripping.

Large iron particles in the thread grooves: This is easy to understand, for the same reason as mentioned above.

Excessively short effective threads of the wheel bolt: In the modification of lightweight wheel nuts, similar problems are sometimes encountered. The effective threads of the original wheel bolts are too short, and after installation, it is found that the threads of the socket nut are not fully engaged with the bolt. Eventually, thread stripping of both the bolt and the nut occurs during nut removal.

Insufficient mechanical strength of the nut: Currently, domestic heat treatment processes are quite advanced, and mechanical performance failures of products are becoming increasingly rare—except when individual customers choose low-end products.

Decarburization of the nut thread tips: This is easy to understand. Thread decarburization is equivalent to insufficient mechanical strength of the threads. It may occur occasionally during the heat treatment process or for products left on the heat treatment mesh belt. Ultimately, we need to optimize the production process, as well as the machining and tapping processes after heat treatment, to ensure process stability.

Eccentricity between the nut end face and the threaded hole: In fact, thread stripping caused by this problem is often overlooked by many people. Thread eccentricity not only may cause thread stripping during installation but also poses significant risks to the fixation between the nut and the wheel. It must be taken seriously.

Excessive installation torque: This risk exists but is rare, as most installation workers know to use appropriately matched torque tools.