At some point you'd hit the maximum safe RPM limit of the motor. Tesla tends to use motors that can run at very high RPMs, but eventually centrifugal force wou

At some point you'd hit the maximum safe RPM limit of the motor. Tesla tends to use motors that can run at very high RPMs, but eventually centrifugal force would damage or destroy it. Also the bearings might wear out. I don't know if the software limit is set to match the RPM limit of the motor, but it makes sense that they would. Also, AC motors tend to lose power and efficiency if they're pushed beyond their optimal range. If Teslas are already at the RPM limit, they could get a higher top speed by changing the gear ratios, but then you'd have less power at low speed. Since hardly anyone actually drives at 155MPH, it's sensible to optimize for the way the cars will actually be used almost all of the time.