There's no single answer to what size wheels a Chrysler M has. The Chrysler "M" refers to a range of models (the Chrysler 300M, and later the Chrysler Concorde, Intrepid, and LHS were all part of the "M" platform), and wheel size varied depending on the model year and trim level.
To know the wheel size for a specific Chrysler M car, you'll need to provide the year, model (300M, Concorde, Intrepid, or LHS), and ideally the trim level. Then you can look it up in a repair manual, online parts databases, or the vehicle's documentation.
