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classic instruments speedometer calibration
Classic speedometer calibration is a mechanical process used to verify the output of the speedometer based on the true driving speed of the vehicle. Speedometer is a measuring tool, usually installed on the dashboard of each motor vehicle or ship. The purpose of speedometer is to provide the driver with accurate driving speed indication. Like digital speedometer, analog speedometer can be calibrated with analog speedometer and digital speedometer and set with hairpin or strong magnet. The speedometer calibration takes into account the transmission ratio in the drive cable, the tyre size and the final drive ratio in the differential. These three items will affect the accuracy of the speedometer. The gear ratio determines the rate at which the speed increases or decreases, regardless of the transmission type. The tire size is correct for calibrating the speedometer.
One full turn of the axle turns the tire one full turn. If you change the tire size, the vehicle will more or less cover the ground at the same tire speed. Remember that speed is the distance traveled divided by time. The speedometer provides information about the time required for a tire to rotate and the time required to complete the rotation according to the distance. A change in tire size will change the ground area covered. The speed reading provided by the speedometer will be lower than the actual driving speed of the vehicle. The final transmission ratio in the differential determines that the change rate of vehicle response acceleration or braking request has an impact on the speed calculation of the speedometer. If the ratio is incorrect, incorrect information may be caused. When the vehicle's tire size changes, the speedometer calibration must be completed. The magnetic field can be corrected by adjusting the hairspring or modifying the magnetic field strength.
A powerful electromagnet is used to adjust the internal setting of the speedometer so that the magnet moves the speedometer back and forth. Check the results carefully to ensure that they are correct. Compare the speedometer value with the input of the rotary drive cable to test the result. The special equipment required for data access can be purchased in the local garage. This simple test is very fast, which can ensure that the speedometer is correct.
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