Speedometer is off by 2 mph.

[fritz_t_coyote]

quote:Originally posted by Knucklehead

Help please. Stock tires, and everything else. Tires are inflated to 35 psi. At any speed between 20 mph and 90 mph the speedometer reads 2 mph faster than I'm actually going. I have checked it with GPS, radar "your speed is" signs, and by measuring with the mileposts at constant speed. Dealership says everything is as it should be. Part of the puzzle is that the error is consistently the same at all speeds.

If the speedlimit is 65 mph, then I want to be going 65.4999 mph. I'm nervous having to always guess on half way between the tick marks.

Thanks for any suggestions
Knucklehead

Auto speedometers are inherently inaccurate, they grow less accurate with age, as tires wear down, and parts wear out. Most are made to read slightly high, erring in favor of you not getting a ticket from a cop with a bug up his behind.


If you are that concerned about it, invest in a high-precision, rally-grade GPS. It can give you a real-time level of precision that is sufficient for rally times, which are about as anal as it gets.