Iâ€™m not sure what it would â€œthrow offâ€?, but there is really no reason to turn rotors unless they are warped, in which case itâ€™s really better to replace them. Instead of having them turned, what you might want to do is "knock them down". This is basically sanding the rotor surface to knock the shine off. Itâ€™s easiest to do with a power (electric or pneumatic) sander and rough-grit emery paper. The objective is not to get rid of the grooves in the rotor (like turning would do), but only to get rid of the shine. Shiny rotors combined with new pads that have not yet seated to the groove pattern on the rotors will cause excessive heat to be reflected back onto the new pads and can cause them to crystallize.Rotors should NOT be turned per MB. This could throw off lots of stuff.