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husker boxster · 06-07-2007, 01:49 PM

I have come to the conclusion my speedometer is off by 3mph also. Curiously it doesn't seem to be a percentage based on the speed but appears to be a constant 3mph across the board. This is based on the speed signs, but from different cities and states. Would they all be wrong by exactly 3pmh? Seems too coincidental. Except for the set of tires I currently have, the previous sets were to factory specs. I have not checked speed with the new set I have on now which are a size or two larger than stock but still 18's. I also wondered if the odometer was registering more miles based on the "higher" speed, so I checked using mile markers on an Interstate. I went 10 miles and the odometer said exactly 10 miles to the tenth.

Is there any way to correct the speedometer?

06-07-2007, 01:49 PM	#4
husker boxster Registered User Join Date: Sep 2006 Location: Omaha Posts: 2,867	Objects Going Slower Than They Appear I have come to the conclusion my speedometer is off by 3mph also. Curiously it doesn't seem to be a percentage based on the speed but appears to be a constant 3mph across the board. This is based on the speed signs, but from different cities and states. Would they all be wrong by exactly 3pmh? Seems too coincidental. Except for the set of tires I currently have, the previous sets were to factory specs. I have not checked speed with the new set I have on now which are a size or two larger than stock but still 18's. I also wondered if the odometer was registering more miles based on the "higher" speed, so I checked using mile markers on an Interstate. I went 10 miles and the odometer said exactly 10 miles to the tenth. Is there any way to correct the speedometer? __________________ GPRPCA Chief Driving Instructor 2008 Boxster S Limited Edition #005 2008 Cayman S Sport - Signal Green 1989 928 S4 5 spd - black 1987 928 S4 - Granite Green Metallic (Felsengrun) Last edited by husker boxster; 06-07-2007 at 01:56 PM.