I have a Model 3 and the Modern Spare for it. The rolling diameter is 26.5. The lug pattern for the Model Y MS is identical, but the rolling diameter is 27.7". So the wheel will fit but the overall diameter is 1.2" less for the Model 3 version that the Model Y. That means the difference in radius, or height difference of the car due to the slightly smaller spare is only 0.6". Modern Spare responded to this question saying the size difference was too great and I needed the Model Y spare. However, I'm interested in hearing from mechanics with experience whether 0.6" radius difference is really a problem. Given so many cars that carry spares this days carry the reduces diameter ones, I can't see that 0.6" is critical at all since the tire is used only temporarily.