Five hub screws are used in all the expensive cars.
Many people would think so, the more the more secure screw wheel, because the more screws, so it can run faster and safer, so it actually? The author thinks that the number of traffic safety and screws never mind, a very simple example, Chanticleer F1 racing feet only a screw yet, but it can run over 300km/h speed, unless there is no screw fixed, otherwise, it becomes very unsafe".
Nevertheless, the original wheel rim of the middle and advanced vehicle was equipped with five screws. Compared with those of the four models, most of the models that made up of the eight screws left a cheaper and lower impression. For some people, some details can be added to the score, while some people have the mentality of "buying iPhone for a protective shell", but they do not exclude the worry that "a single screw" brings.
In fact, when designing this aspect, whether it is four or five screws, it will pass fatigue test, friction coefficient test, road test, bench test and so on. It can be said that there is no Jerry building or safety problem. The results show that the number of wheel screw is related to the weight and load capacity of the body. If the number of screws in the rim is less, then the load state of each screw is greater. In this case, we must use thick screws or screws to meet the safety needs. For example, if the vehicle weight reached GK5 2000kg (adjective), then it in turn, uneven pavement when the lateral force of rim of the bear will become large, and become very uneven, and the screw can make contribution is that its capacity must be large. Of course, much larger than the five screws of four screws to withstand torque.
The way to solve the problem can be a variety of first - as mentioned above, either four or more; second is the strength of the screw (the most common), and the detailed answer this, interested can go to, there is no detailed discussion, here a simple for example: like, models, the original standard screws (bolts) the strength of grade 8.8, this is a low numerical strength, using five hole wheel set, have enough to use. On the other hand, if you are using a bolt strength higher level, so the four bolts can meet the requirements (there is no need to waste, as well) and the generation of Smart only three screws, a new generation of models into four screws, the screw strength will be adjusted accordingly. Of course, the number of screws does not depend on the size of the ring, like a number of cars using a 17 inch ring, but still can be designed with four holes.
Interpretation: in general, the small car tonnage is small, at the same time, it is not used to carry goods, so the rim four screws are good enough, if the car is larger, and to cope with the 7 full weight, most of the rim is form five screws. Of course, you also don't forget wheels bearing this important data quality, and equipped with wheels designed for small car design, even if the rim PCD other models of the same value, but in the intermediate car is too high (dangerous), and the rim small screw involves the key torsion bear, as for those truck motionless is 8 pieces of 10 screws, is also very easy to understand?