Vehicle mileage is a major indicator of technical condition. On it you can judge whether the machine needs urgent maintenance or not. He plays an important role in the field of automobile sales in the secondary market. Everyone who is interested in buying a used car, first of all, is interested in the seller, what distance he covered. It’s good if you come across a responsible seller who does not use speedometer windings. But this does not happen so often.
The distance traveled, several hundred or thousand kilometers long, can tell a lot about the car. Are its components intact, is there a need to replace consumables, or can you wait a while? The lower the mileage, the higher the cost can be requested. Some owners do not go to any tricks to sell the car as profitably as possible. What is this ingenious invention and is it easy to make it yourself?
Forced reasons
The number of people who want to make a small adjustment to the readings is a lot. This suggests that the phenomenon is quite widespread. In this case, each owner will be able to find a worthy explanation for his act. Basically, everything is attributed to a faulty speedometer or the need to replace the instrument panel.
But if you are frank to the end, then the main reason for winding the speedometer is the desire, at least to some extent, to rejuvenate your car. And, as a rule, making the necessary adjustments is done for the purpose of further sale. The so-called pre-sale preparation. It is much easier and more pleasant to sell or buy a car with low mileage.
Both sides benefit: both the seller, who got the price, and the buyer, who, it seems, got a relatively new car. Therefore, the topic of mileage wrapping is the most discussed among a large number of former and future vehicle owners.
In addition to those who want to reduce mileage, there are those who are trying to increase it on the contrary. These are mainly drivers of commercial vehicles or vehicles used for service. There is also an excuse for this, and on the one hand it is quite justified.
Those fuel consumption rates that the accounting department of almost any enterprise takes into account cannot cover the real costs of gasoline or diesel fuel. And the winding of the speedometer allows to some extent solve the problem, since the size of the compensation that is required when using a personal vehicle is mainly able to cover only fuel costs. That's just the depreciation and wear and tear of the car are not taken into account. In this connection, many drivers go to such a necessary measure.
Speedometer and odometer
Everyone knows what a speedometer is. This is a device that shows the speed of a car at any given time. But there is also such a thing as an odometer. Someone has already heard this term and knows what it is about, but not everyone is able to understand what kind of device it is. Meanwhile, it serves to measure the distance traveled by a car.
In fact, the speedometer is a combined device that combines a speed meter and a mileage monitor from the date of issue. In some cars, in addition to the odometer, there is another device - a mileage counter per day. To reset it, a special button is provided (something like a speedometer winder).
Since the odometer is mounted directly in the speedometer, many drivers often call these two devices a common word - speedometer. Which is not entirely true, because the function of the speedometer is to measure the speed of the car, and the odometer measures the path traveled by it.
Varieties and principle of operation of speedometers
In cars, you can find a different type of distance and speed meter, but as a rule, there are two main varieties:
- mechanical (analog);
- electronic (digital);
- electromechanical (combined).
Mechanical speedometers are also divided into several types and can be:
- centrifugal;
- chronometric;
- vibrating.
Electromechanical devices are divided into electromagnetic and induction. This is important to know, since the use of one or another scheme for winding the speedometer with your own hands depends on it. Indications, regardless of the type of device, are displayed in km / h, and in the United States - mph (miles per hour). How exactly is a speed measurement made?
There are innovative speedometers that can determine the speed of a car using a satellite positioning system (GPS, GLONASS). However, such systems are not installed at the plants and are rather an additional option, which significantly increases the comfort for drivers.
Mechanical speedometer
The principle of operation of the device in cars with rear-wheel drive: the speedometer calculates the speed reading from the gearbox output shaft. In this case, the accuracy of the readings is affected by the size of the tires, the gear ratio of the rear axle gearbox and the device’s own error.
To measure the speed of front-wheel drive cars, the speedometer is based on the left wheel drive. Here, in addition to the error of the device and the size of the tires, the so-called effect of curvature of the road affects the readings. That is, when you enter the left turn, the speed will be less than the rectilinear movement. If the car turns right, then the speed on the contrary will be slightly increased. The do-it-yourself mechanical speedometer winding scheme is not so complicated, as will be discussed later.
Electronic speedometer
Almost every modern car is equipped with an electronic speedometer. Perhaps, after a certain time, it will completely replace the mechanical analogues, but so far they are still present even in new models. The principle of operation of an electronic device is simpler than that of a mechanical speedometer.
Often an electronic device has a magnet in its device that is mounted on the output shaft of the gearbox. The magnet rotates with the shaft, and the electronic unit is located nearby. At the same time, rotating around the circumference on the gearbox shaft, the magnet periodically passes in the immediate vicinity of the electronics, transmitting a signal to it and thereby performing the function of a sensor.
And every time a magnet sweeps past a block, it sends a pulse to the speedometer. Inside the meter there is a so-called black box (characterized by increased ingenuity), which calculates the speed of these pulses. To do the winding of the speedometer, this knowledge will not hurt.
There is nothing easier to understand: the faster the pulse transmission frequency, the faster the shaft of the box rotates. All calculations are performed with maximum accuracy and have almost zero error.
Inaccuracies
It happens that metering devices record the wrong speed of the car. On the one hand, it’s even good when the speedometer shows slightly increased readings. In this case, the driver will comply with the speed limit and will not receive a fine. And manufacturers are calm, and drivers do not violate traffic rules.
Another thing is if the device, on the contrary, underestimates the real speed. Then many companies would simply go bankrupt in numerous lawsuits from drivers, which indicate that the cause of fines or emergency situations were incorrect speedometer readings.
Why do errors happen? The fact is that this device does not differ in increased accuracy, since the rotation of the wheel of a car is mainly used to determine speed. In this case, its diameter is taken into account, and this parameter is not stable. It is important to know this when deciding how to rewind an electronic speedometer or a mechanical one.
Speedometers on many modern cars have an average error of 10% at a speed of 200 km / h. But the dependence is non-linear. That is, at a speed of 110 km / h, the difference with the real one can be 5-10 km / h. But if you drive slower (up to 60 km / h), then the error is so small that it can not be felt.
Cost calculation
For many, the price of the issue is a fundamental factor in almost everything: purchases, services, and so on. In this connection, it is reasonable to ask yourself the question of how much the speedometer correction, so necessary in some cases, will cost. Here, as during any work in the auto repair shop, it all depends on the complexity of its implementation and volume.
It is not so difficult to mess with mechanical speedometers, all that is needed is to rotate the mechanism's drive in a certain direction. There would be time, and desire will always be found. However, with electronic metering devices, everything is much more complicated than it might seem. Here you need basic knowledge of the electrical equipment of the car. And in some cases, one cannot do without the knowledge and skills of a programmer.
Currently, in many stores that have their own website, you can buy a speedometer winder with adjustable winding speed. There are various options for sale, and any car owner will get what they want.
The first electronic speed meters recorded mileage on the internal memory, which made it relatively easy to adjust the values. In many modern cars, the necessary information is duplicated among the electronic units of different systems (ECU, brake, lighting, immobilizer, etc.). This data is well encrypted.
To correctly carry out the procedure, you need to edit the data wherever it is. This significantly complicates the matter, in addition, you need not to touch on important indicators of other systems. If you turn to a layperson, you should be prepared to buy any new part, possibly not one. In addition, the work itself will cost a lot.
As for the cost of competent adjustment, the prices vary significantly and depend not only on the brand of the car, but also on the year of manufacture. For example, for a UAZ Patriot car, the price can start from 1,500 rubles. The owners of the new Land Rover car will have to fork out 15,000 rubles. There are companies in which the price of such work can reach 25,000 rubles. It may be worthwhile to purchase a speedometer winding circuit with adjustable winding speed and do it yourself.
Twisting a mechanical speedometer
If there is no extra money or a desire to entrust your car to unauthorized persons, you can do everything yourself. True, with mechanical devices, as described above, messing around is easy, there would be time. To do this, disconnect the device cable from the box and fix it on the shaft of some motor. A drill is also suitable, which will be even better.
Having chosen a direction, start twisting. It will take a lot of time, due to the high gear ratio of the gearbox. You can use another way - to dismantle the odometer, then using a special tool and brute force, set the necessary readings.
Electronic device winding
To correct the readings of electronic devices, you must use special equipment and computer programs. You need to know exactly where to look for data, which is difficult. But often all the information is collected in one place.
The electronic speedometer is rewound by reprogramming the current data of the car blocks. You can use one of several connection methods:
- directly to the data schema;
- through the connector in the dashboard;
- through the diagnostic connector.
Rewinding an electronic speedometer is a complex procedure that borders on certain risks. Despite this, it is often used, because you can significantly increase the cost of the car, which is only in the hands of sellers.
Can speedometer twist be detected?
It all depends on the type of device. If it is an electromechanical or mechanical device, then just look under the car and inspect the drive box. In the presence of contamination and unusual traces, we can conclude that the speedometer readings were corrected. If the drive is clean, then with high probability everything is normal. Already a proven fact - 50% of vehicles from the total number of vehicles on the secondary market have incorrect mileage.
If the car has an electronic speedometer, then it is already more difficult to detect extraneous interference. But to connect the winding of the speedometer in this case is also not easy (at least some comfort). Without an experienced craftsman and special equipment just can not do. Often in car repair shops, tags with accurate mileage data are attached to the car. This is done during maintenance or after replacing parts of the fuel system. It is worth comparing the data from the tag and the speedometer. If they coincided, then there is nothing to worry about, otherwise there is a possibility of fraud.