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In fact, within the complex structure of a car, the screws on the wheels (often referred to as hub nuts) play a crucial role. They not only ensure a secure connection between the wheels and the vehicle, but are also directly related to the safety of driving. Without these nuts, even the most expensive luxury cars would not be able to safely travel on the roads.

For those who are familiar with cars, they may notice that the number of hub nuts on different models of vehicles varies. Some large vehicles or heavy-duty trucks may have as many as seven or eight or even more hub nuts, while some small vehicles may have only four. As for those racing-specific F1 cars, due to their special design requirements and competitive performance considerations, they only use one hub nut, which is unique in terms of aesthetics.

So, how is the number of hub nuts on a car determined? Why do car manufacturers on the roads prefer to use multiple hub nuts rather than a single one? 

Hub nuts on cars
Firstly, it is not the case that the more hub nuts there are, the higher the safety level. Before the cars leave the factory, they undergo rigorous tests such as fatigue tests, bench tests, and road tests. Therefore, whether there are 4 or 5 hub nuts, it will not affect driving safety! For example, in F1, to facilitate tire replacement, only one screw is used, but the car can still reach a speed of over 300 kilometers per hour, which is absolutely safe.

Why don't we see single hub nuts on ordinary road cars? 
This is because a single hub nut has to bear the entire weight of the wheel (instead of being shared by four or five), and the torque required for disassembling/installing a single wheel lock is incredibly high. This means that if you want to change the tires of a car with a single hub nut but don't have electric tools available, you will be very frustrated, and cars with single hub nuts will require custom electric tools, which will add an extra expense. In contrast, cars with multiple wheel nuts don't have this problem because most tire shops have designated tools to handle them.

Although the idea of a single hub nut is aesthetically appealing, it requires more care and precision during installation. If it is not installed correctly or not tightened enough, and when you are driving, the wheel will come off. Take F1 racing cars as an example, even the most skilled technicians and maintenance staff at the race track may install the wheels incorrectly. Ordinary tire installers are not as skilled and precise as F1 racing car maintenance staff. They must handle more common vehicle models. If there are multiple hub nuts, if one of them fails, at least the other several hub nuts can serve as backups to keep the wheel in place. 

This is why car manufacturers for highways tend to use multiple hub nuts rather than a single one. Obviously, when manufacturing racing cars, the ultimate goal is speed, weight reduction and winning the race. This is in contrast to highway cars, which need to consider cost, durability and lifespan. 

Hub nuts on a car
• The more hub nuts there are, it doesn't necessarily mean the car is of higher quality. The fewer hub nuts there are, it doesn't necessarily mean the car is of lower quality.
• The number of hub nuts has no direct and inevitable relationship with the car model or its weight. It is related to mechanical reasons.
• The number of nuts on the hub mainly depends on the screw mechanism, axial force, thread torque, thread friction coefficient, end face friction coefficient, end face torque, etc.
• According to the general fastener testing method formulated by the National Mechanical and Electrical Department, hub nuts can also be equivalent to the testing method and error standards of GB52 hexagonal nuts.