Speedometer calibration versus wheel size

[hybridtwins]

All,

Does anyone know if the speedometer of the 2010 Prius is calibrated differently depending on whether you order a factory package that includes 15" wheels versus a package that includes 17" wheels?

[fuzzy1]

Originally Posted by hybridtwins

All,

Does anyone know if the speedometer of the 2010 Prius is calibrated differently depending on whether you order a factory package that includes 15" wheels versus a package that includes 17" wheels?

I don't know directly, but it shouldn't need a different calibration, or at least not much. The raw 17" tire diameter is 1.5% less than the 15" tire, but this does not account for effective rolling circumference. For the simple-minded calculation, see the earlier preliminary Prius info thread.

[hybridtwins]

Originally Posted by fuzzy1

I don't know directly, but it shouldn't need a different calibration, or at least not much. The raw 17" tire diameter is 1.5% less than the 15" tire, but this does not account for effective rolling circumference. For the simple-minded calculation, see the earlier preliminary Prius info thread.

Also a related question: since turning diameter is about 2 feet larger with the larger wheels, would a mechanical adjustment have to be made to the steering if one size wheel were swapped for another by a dealer?