Good day to all! For a long time I have published articles on car tires, this is an interesting article where I told my sad experience and. Today, I will deviate from this topic a little. Do you know what a disc ejection is and what this parameter affects? I'm sure a lot of people have no idea about this. Well, since it is customary to consider a variety of interesting publications on automotive topics in our blog, we will follow this trend. Let's get acquainted with the concept of disk departure closer.
It is believed that this is one of the key parameters related to the field of geometry. There are permissible deviations, and if they are violated, then such a disk will even be difficult to install on the wheel hub. However, in many forums, the debate continues on the topic of how much the deviation can differ from the regular one.
A small amount of deviation, in principle, allows the operation of the wheel, especially if it is written in the instruction manual for your car. Sellers in car dealerships can say something like this: if the wheel does not catch on the suspension or body when driving, then you can put it on and ride. This is not surprising, since their main task is to sell these discs and all related equipment.
How is it calculated and labeled
In order to answer the question "how to find out the drive offset", you need to start with what this value represents. At its core, this is the distance between the vertical value of the wheel plane and the plane in which it is applied to the wheel hub. It is expressed in millimeters. Therefore, the overhang can be not only positive, but also zero, or have a negative value. The distance between the centers of the wheels along the same axis depends on it.
For the same car model, the maximum offset with its allowable deviations will be the same, according to the recommendations of automakers. This criterion is coded ET followed by a number. It means the actual distance in millimeters. You can meet this designation directly on the disk itself. For example, ET 0 (zero overhang), ET-15 (with negative overhang), ET 40 (larger, positive overhang).
Why is it important to adhere to factory offset values
Even a slight deviation from this parameter from the values \u200b\u200bdeclared by the manufacturer is undesirable. The fact is that this affects the conditions in which the entire suspension and its individual components will have to work. By changing the value, the load on them increases, and this will certainly lead to their early failure. At the same time, in individual car models, this parameter may well be different from each other. It's just that when designing a car, designers deal with a huge number of various parameters that have to be adjusted, and on which the requirements that apply to the entire suspension will depend. 
Without delving into the discipline “Car Theory”, I will comment on the figure. Fig b - as it should be, that is, the parameters of the rims correspond to those declared by the manufacturer. Figure a, c - deviation of the departure parameter, either in “+” or in “-”. You can see for yourself how the load will be applied (blue color), and this leads to increased wear of the chassis elements, primarily wheel bearings.
Even the mass of the engines already has an effect on the suspension, and this load must also be taken into account. The design should provide maximum reliability. At the same time, not only the level of comfort, but also the controllability of the vehicle itself must be maintained. An increase in the calculated offset value in relation to the factory one forces such a wheel to sit deeper on the hub during operation.
Due to the displacement of the central axis of the disks, a displacement of the steering axis will inevitably occur. As a result, the controllability parameters of the car, provided by the designers, will change. Well, and, as a result, a change in the moments of forces exerting their influence on the suspension, and this is already unsafe for movement. Today, on sale you can find spacers - special devices that allow you to mount discs with a non-original offset. To use them or not, let everyone decide for himself. 
Today we could see how to determine the offset, how important the disk offset parameter is, and why this should not be neglected.
If the wheels of your vehicle are chosen correctly and the car itself is in good technical condition, then you can drive it even to the ends of the world. The topic of travel is relevant all the time, someone plans their vacation a week before departure, and someone 6-7 months in advance. Be sure to read articles about on the way to the Crimea and about the features of renting a car abroad: and. Read the blog further - there are many interesting things ahead, and most importantly, useful for any motorist. Until we meet again, friends!
