The wheel fastening methods can be roughly divided into two types, namely the Wheel Lug Bolts method and the wheel nut method. So how do we tighten the bolts? Let's learn about it together.
For the connection structure of 5 commonly used Wheel Lug Bolts. If a steel wheel hub is used, its clamping force should be ≥35KN, and if an aluminum wheel hub is used, its clamping force should be ≥25KN.
Taking into account that the Wheel Lug Bolts need to be reused, after the Wheel Lug Bolts are tightened 5 times, its clamping force still needs to meet the requirements of ≥35KN for steel wheels and ≥25KN for aluminum wheels.
In terms of torque, the recommended process torque is 120Nm, and the maximum does not exceed 140Nm. This data is the assembly torque used in the general assembly workshop.
The yield torque of Wheel Lug Bolts is basically above 180Nm-200Nm. From the design point of view, the process torque is much lower than the yield torque. This is also to make Wheel Lug Bolts always used in the linear section of the tightening curve. After repeated use, the performance will not decrease.
Therefore, for the position where the wheel is connected, when repairing and tightening, a fixed torque wrench or a digital display wrench is required to tighten, and the tightening torque is about 120Nm or tightened to the torque of the original factory assembly of the vehicle.
When using a non-fixed wrench, you must choose an experienced maintenance master. Such a maintenance master probably knows how long the sleeve is? How much angle is twisted? How much torque can be reached?
Through the above analysis, the design of the position of Wheel Lug Bolts has a certain torque safety margin. But if the master keeps twisting it to death and uses his whole body strength to step on it, the torque will be difficult to control. If this is the case, it is recommended that you don’t repair it here. Even if there is nothing wrong now, the service life of related parts will be affected. We who are engaged in tightening should all know that tightening and tightening to a certain angle and torque are completely different concepts. As an engineering technician, everything is based on data, not almost.
Over-tightening of Wheel Lug Bolts will cause the bolts to yield excessively and produce irreversible plastic deformation; over-stretched bolts are prone to breakage when subjected to external loads; the thread load on the handpiece is large and the thread is prone to slipping; the surface of the handpiece is prone to crushing and other problems.
When repairing, it is best to use a fixed torque wrench to tighten the Wheel Lug Bolts. The tightening torque is recommended to be 120Nm or the original factory assembly torque, and the maximum is generally not more than 140Nm; if a non-fixed torque wrench is used, it is recommended that an experienced maintenance technician tighten the assembly, and it is not recommended that the technician use all his body strength to tighten it to death; the assembly sequence is pre-tightening first, and tightening one by one in the diagonal direction when tightening.
