So, I bought my truck used, with larger than factory tires on it, and now I'm confused.
I noticed when driving to Dallas in my (stock) BMW that the mileage was 248. When I drove the truck a couple weeks ago, the mileage was 221 (yes, same route...
. This caused me to call into question my odometer reading, and also my fuel economy. If this is true, my odometer reading is low, and the fuel economy I'm showing is also low (at least using the in-dash computer, not by calculating by hand). The strange thing is that the speedometer is correct, at least according to driving next to my brother, and the LED speed things on the road.
Am I missing something here? Does anyone know how the mileage and speed are computed into the dash? I would have thought it would be axle ratio/tranny ratios, etc, computed from a preprogrammed tire size, which would be fine if the speedo was also off... Any thoughts?