So if I removed my 18" wheels and put on a set of 15" with a drastically smaller diameter, and the speedo was off by 15 MPH, you're saying my odometer will not change?If you believe that, then try this
I will actually try to make note of the mile markers next road trip...worth the try for science.
I hear you, but my 2005 Sienna had no clue where it was....no GPS, no tracking....odometer based off speed.Not exactly.
What I think @supton is saying is that the computer is calibrated to determine both speed and distance accurately, let's call it "base value," but this data is then further manipulated, let's call it "adjusted value". The adjusted value could be something simple like adding a couple of kph or mph to the base value. The car then uses base value for tracking distance, but sends adjusted value to the speedometer to be presented to the driver, for the reasons already mentioned earlier.
On my old BMW, I could access the internal computer to see both values - base and adjusted, but only the adjusted value would be shown on the main speedo.
Interesting about the BMW.