Generally speaking how does larger tires/rims change the speedometer & odometer readings.

I installed larger size tires/rims on a F150 Larait.

1. Does this make my speedometer read higher than I'm actually going or slower than I'm actually going.

2. Does this make my odometer add more miles than I've actually traveled or subtract miles from what I've actually traveled.

Thanks

 

Your speedo will read slower than you actually are going. You will read less miles on the odometer as it is tied directly to the speedo. You can go to a Ford Dealer and get the PCM re-calibrated to read the larger size tires at the correct speed.