EMERGENCY AID! THE SERIAL COUNTER OF THE KM

Hello, I would be very happy if you read it to the end .. I know that the km / speed indicators of the vehicles are wrong. While the dial shows 100, it's actually like the actual speed is 95. Today I took a measurement with the gps program to calculate the percentage of deviation on the coastal road. The vehicle showed a speed of 100 km while the GPS was like around 92-93. When I went up to 100 km according to GPS, the vehicle showed around 112-113. The deviation came too much. I thought that this extreme deviation would also affect my kilometer counter, that is, it would write more than the km I went. I pulled to the right, reset the trip, and activated the distance meter feature in the Gps program and continued on the road. According to GPS, I actually traveled 10 km. And when I looked at the meter of the vehicle, I saw that it wrote 11.8 km. So according to this calculation, the vehicle writes 18% more km. Since I bought this vehicle, I have made 20 thousand-odd km. Roughly when I made an account, I actually went 16 thousand km, but the car shows that I went 20 thousand. Do you think this is possible? Is there a possibility that such a deviation may occur? I am very bored with this situation. If so, I don't know what to do. Could it be due to tires? The tires are smaller than the original size and the owner before me used an average of 10 thousand km. I'm about to eat the head. I even became a thinker to drop miles. Please help me.. oguzhankucuk61 2016-12-01 02:03:28

rim tire sidewall calculation is important. It is normal to go with 95 while showing 100.

Let me give you an example I live

Vehicle Tofaş Şahin 89 models (we boarded for 15 years)

Original 13 wheels 175 with 70 tires 100 shows 90 would go.

15 rims 195 shows 100 tires with 45 tires would have gone 100. (I calculated and bought )

13 rims would go around 85, which shows 100 with 180 60 tires.

With the last rim, the car showed 180, while the GPS was 155.

With 15 rims, the car would go the same as the gps.

The car calculates its own speed with the number of turns of the tire. (I am going to turn 80000 turns at 100 km. If the circumference is shortened by 1 cm, it will make 800 meters of error so that its circumference is close to 2 meters.) If the circumference of the tire shrinks, it will go slower as the car shows. In other words, if you do not use the exact measurements given by the factory, the margin of error will be impaired. Simple circle environment calculation.

Do you think there is such a difference in the case of 175/65 14 that should be 185/65 14?

The rim width does not affect deflection, but it does affect fuel consumption.

Diameter affects bias only.
In the past, commercial taxis used to wear smaller rubber tires than the original. Because the number of turns will increase, the mileage will be more than it should be. This will be reflected in the taximeter.
This is of course valid for the old generation vehicles we are saying.
In the old system, transmission was made from the mechanical moving device to the tachometer, where the mileage wire was used.
In the new generation, the situation is different.
Logical calculation is done digitally from speed sensor, bsi brain, gps, obd protocols.
This means water. The engine speed is calculated by the speed sensor ratio.

The only reason for the deviation in your vehicle may be the electronic malfunction in the tachograph. You are a driver with the original rim of the known distance, then you make the same path with a different diameter tire and observe the difference in between.
In return, you also provide the way you came with the tire you came.

If you read different values at the same distance each time, you will realize that it is not a tire diameter but a tachograph error.

Good day everyone ...

thank you to those interested. I took another measurement today. Yesterday I measured it wrong, I did not understand what is the GPS or the head seven, but today I calculated that it is 5%. If I turn the tires back to the original, this ratio will decrease even more.

My winter tires are fitted with original 14 "wheels, my current summer tires are on 16" wheels,

It is useful to look at. The more the km shows, the more the meter says.