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what is Car Wheel Screws? | JWHEEL

Hub screws, called NUTS. To the car owners, it should be a very inconspicuous accessory. Except when the tire is being replaced, it will be moved, and he may not pay attention to it or look at it at ordinary times.


2022/09/29

Hub screws, called NUTS. To the car owners, it should be a very inconspicuous accessory. Except when the tire is being replaced, it will be moved, and he may not pay attention to it or look at it at ordinary times. 

If the hub of your car is 4 holes, then there are 16 hub screws installed on the 4 wheels; if the hub of the car is 5 holes, then there are a total of 20 screws on the 4 wheels.



     

1. Types of hub screws:

The first is the most common nut. Generally, Japanese cars and American cars basically use this form of wheel hub screws. using this nut

For the model, the screw is on the flange of the axle head of the car. When removing the hub, we only need to unscrew the nut. It is also relatively convenient and quick to install the hub.





 

The second is the screw, also called the bolt. General European cars include German cars (such as ABB, Porsche, Bentley, etc.), French cars (PSA, Renault) and Italian cars (Ferrari, Lamborghini, Fiat, etc.) that use this form of screws. Screw the screw into the screw hole on the flange of the shaft head to fasten the hub.

 

Since Chinese self-owned brand cars have absorbed the car-making experience of many different advanced countries, the types of wheel hub screws are relatively uncertain, but generally they are one of the above two types, either nuts or bolts.



The third type is the reverse string screw that will be used in the modification industry.

The reverse string screw, also known as the reverse screw, has both ends of the wire, one end is attached to the shaft head, tightened with the required torque, and the other end is tightened with a nut to fasten the hub. Why use reverse screws? One is that it is easier to replace the hub. German car owners, especially those who have disassembled and installed the hub themselves, will have a deep understanding: when installing the hub, there will be an embarrassing situation of not aligning the hole position for a long time, especially in harsh environments such as rainy days and high-speed edges. Replacing the wheels can be maddening. German cars generally use screws to fasten the wheel hub, while Japanese cars extend the screw from the flange and fasten the wheel hub with nuts. Although the effect is the same, but holding the wheel hub in one hand and pinching the screws in the other hand to find holes, it is really tiring. people! In addition, today's wheel hubs are getting bigger and bigger, and they are always 19 inches or 20 inches. One hand? I am also drunk. Japanese cars come with several screws on the horns. After putting on the hub, you can fasten the nuts, which is very easy. Therefore, the reverse string screw can "transform" the European car into the form of the upper hub nut of the Japanese car, so it is called "reverse string".


                    


For other reasons, for example, if you want to widen the wheelbase, or change the big brake, if the wheel hub cannot pass the brake, then you need to add spacers. If the spacers are thick enough, your screw is not long enough, and it will eat silk. The number of laps will be insufficient, and in the case of intense driving, it will lead to various safety problems. Because the length of the reverse string screws can be flexibly customized, on the other hand, the nuts can also be replaced more flexibly, such as anti-theft nuts, lightweight and high-strength nuts, etc.


   


The fourth, the least common and highest end central locking screw.

Central locking screws are generally found in professional racing cars, such as F1 and so on. Because many racing games may require one to three tire changes after a race, a single locking screw can save more than four or five times the tire changing time.

We can also see a single locking screw on some top supercars, such as Ferrari ENZO, Porsche Carrera GTS and so on. The central locking screw will run tighter and tighter, unlike other types of screws that will run looser. And if you want to take it out, the general tire shop does not have tools, you need special tools. Because it gets tighter and tighter, it needs more than 500 Nm of torque to remove it.





The above 123 types of screws can be used with the most anti-theft screws. Let's talk about anti-theft screws.


In general, a set of imported big brand modified wheels is expensive, even the second-hand price is not cheap, then the problem is, if you use non-theft wheel hub screws to install on the car, you may wake up and love the car. It will be like this.





So for safety, we still need a set of anti-theft screws. The anti-theft screw is like a keyhole, you must have a key (sleeve) to open the lock. Generally speaking, as long as there are 4-5 screws installed on a wheel hub, as long as one is an anti-theft screw, it can play the role of anti-theft. So we can see that in a set of 16 or 20 screws, only 4 are anti-theft screws, and the remaining 12-16 are ordinary screw heads, and a special anti-theft sleeve will also be provided.

There is also a double anti-theft screw. There is also a nut plug on the top of the nut, and if you want to unscrew this nut plug, you need to use the matching nut plug key.







Second, the contact surface type of the hub screw:

The contact surface of the hub screw is divided into two types: spherical surface and conical surface.

The contact surface of the wheel hub of the original car is mostly spherical, so the contact surface of the wheel hub screws of the original car is also spherical. However, when modifying the wheel hub, you should pay attention to whether the contact surface of the modified wheel hub is spherical or conical. The modified wheels of Japanese brands (such as RAYS/SSR/ENKEI/WORK, etc.) and European brands (such as OZ in Italy) are generally tapered, and the angle of the tapered surface is generally 60 degrees. The modified wheels of American brands are generally spherical, so they must be installed with appropriate screws. In the picture, you can clearly see the difference between a spherical surface and a conical surface.





If your hub is the contact surface of the conical surface, and you still insist on using the original spherical screw, then you can imagine that the contact area between the screw and the hub is pitiful, and the direct consequence of such long-term use is It will damage the contact surface of the hub, forcibly squeeze the plane into a partial spherical surface, then this set of hubs that may be worth thousands of dollars will be destroyed like this. Moreover, when it is subjected to external shocks during high-speed driving, there is a considerable safety hazard.

And vice versa, if your hub has a spherical contact surface, you cannot use cone screws.




3. Specifications of hub screws

If you see such parameters in the process of purchasing hub screws: M12*P1.25. M represents the diameter of the screw, the 12 behind the M represents the diameter of 12mm; P represents the pitch, and the 1.25 behind the P represents the pitch of 1.25mm. So be sure to understand the parameters of the original car to buy.

Here are some examples:

M12*P1.5 is suitable for: Toyota, Lexus, Honda, Mitsubishi, Mazda, Ford and other brands;

M12*P1.25 is suitable for: Nissan, Subaru, Suzuki, etc.;

M14*P1.5/M14*P1.25 Applicable to: Volkswagen, Mercedes-Benz, BMW, etc.

In addition, there is the length of the bolts and screws, which is relatively shallow. As long as you see how many mm the length is, you can match the car and the wheel.



 


4. Material and manufacturing process

The wheel hub screws of the original car are generally made of steel, and the weight is relatively heavy. The forging screw uses the same forging process as the forging rim. During forging, the metal is heated to the saturated melting point (solid state) and is instantly press-molded with high pressure. The internal air holes of the material are completely absent, and its structure is also due to High-pressure extrusion without air holes, the metal is tightly joined and arranged in a neat and regular manner, so the overall strength of the material is very average, the weight is relatively lighter, and the same or even higher strength can be achieved with less material. In addition, in terms of material, the material we generally see for forging screws is T7075 T6 alloy, and even titanium alloy is used, but the price is staggering enough.

The following picture is the weight of Fit original steel screws:

It can be simply calculated that the weight difference of each screw is 34 grams. Calculated by 16 screws in a car, a total of 544 grams of weight can be reduced. If you count it by 20, it can reduce 680 grams. It is believed that Japanese RAYS and other major manufacturers will be lighter than this ordinary domestic modification screw.

According to a study done by a well-known foreign automobile company, the unsprung mass is reduced by 1 kg, which is equivalent to the sprung mass minus 15 kg. In the field of modification, there has been a saying that one kilogram is unsprung and 10 kilograms is spring. Reducing unsprung mass significantly improves acceleration, braking and handling.

A set of lightweight and high-strength hubs and a set of lightweight and high-strength hub screws can minimize the unsprung mass. Therefore, in the eyes of professional drivers and enthusiastic modification enthusiasts, the original wheel hub screw is a piece of fat that has to be cut off from the car.

For example, each modified wheel hub is 3KG lighter than the original one, and the total of the four is 12KG lighter, plus the screws are nearly 0.6KG lighter, so a total of 12.6KG can be lost. Then according to the multiple of 15, it is equivalent to the performance improvement brought by 189 kg lighter on the sprung. As for whether it is really so divine, we have to slowly practice it.


5. What brands do wheel hub screws have?



RAYS is known by many people in China. As Japan's largest forged wheel manufacturer, the performance of forged screws is also quite impressive. In addition, there are KYO-EI, WORK, BLOX, AJ, etc., 

I believe that after reading this article, everyone has a basic understanding of hub screws. For more knowledge about automobiles, you are welcome to study and exchange together, thank you.


  Jwheel, as an professional wheel manufacturer, concentrates in R&D and manufacturing of aluminum alloy wheels, including casting wheels, forging wheels and flow-form wheels. The products of it have passed the certifications of SEI、SEMA,VIA, JWL, JWL-T, TUV and so on. Since establishment, Jwheel has been developing steadily, with rich experience of designing and producing aluminum alloy wheels. It has earned the appreciation of both domestic market and foreign market with its high technology, good quality and customer service. It provided OEM service to many international brands like Vossen, OE Wheel, TSW, Rays, ProLine, Oxygen, AUTEC, etc., and it also provide ODM service, that is, for producing a new wheel, you can just provide a sketch, drawing or picture, and then Jwheel will finish the rest parts. By the way, the MOQ of forging wheels is four. (For more information, just go to the website: https://www.jjjwheel.com)

                               





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