Why the speed range in speedometer is higher than actual speed of vehicle?

No, it’s not a marketing gimmick. The upper limit of a speedometer, or any other type of gauge or indicator, is selected purposely to be higher than it should ever see, even under extreme conditions.

One reason for this is to prevent damage to the device when it hits the upper stop limit, sometimes referred to as being “pegged.” This is especially true for mechanical speedometers versus electronic types.

Exceeding the upper limit can also cause the speedometer to come out of calibration; in other words, it may not display speed accurately.

One guideline used by pressure gauge manufacturers is that the upper limit should be about two times the intended operating pressure. Applying this logic to speedometers and using 65 mph as a normal maximum driving speed, two times would be 130 mph.

A second guideline is for normal operation to be between 25 percent and 75 percent of the range — in other words to operate in the middle. For a speedometer with the maximum at 130 mph, that is 32 and 97 mph. Certainly, most normal driving would generally fall into this range.

A third guideline is that the speedometer pointer, or needle, be near the 12 o’clock position when driving at the maximum normal speed, say 65 mph. For the speedometer in the photograph, this is pretty much near the 12 o’clock position, which is easiest to see and read.

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