Speedo Brain teaser

stan909 wrote:
I passed four radar signs showing my speed yesterday on highway 126 from Valencia Ca. to Santa Paula.Each showed 51 when I was driving 55 according to my speedo.When I got to Ojai from San Bernardino my trip meter showed 137 miles.Is my odometer correct or did I travel less than that?Does my van really have 109,000 miles or less? I went to San Diego a few weeks ago and got 18.3333333 mpg,filling before leaving and filling upon arrival to calculate,but if my odometer is off what did I really get? I'm not sure I want to know but please chime in.

I don't know how old your van is, but the newer speedometer/odometer seem to separate the two functions. We have 4 vehicles and all, with original tires, read high on the speed vs actual, and high on the miles vs actual. But, they were way off compared to each other. The speedometers always seemed to be about 2mph off, not a % of speed. 2mph at 30, 2mph at 75. The odometers were a fixed % of actual distance off, usually about 1-2%.

If yours is similar, you probably have less miles than indicated. Four miles an hour off is a lot to be off. Time to check it with a gps for speed and distance to know for sure.