slipstick:
Castle do make a sensored 1406 motor which will run more slowly with the correct ESC. But you have a high Kv sensorless motor intended to be used with high gearing. The motor itself will not run slowly.The only practical way to get it a little slower is to use a lower voltage battery. The other way to get the car travelling slower is to change the gearing.
Steve
i found this video on youtube about changing settings on the ESC
Do you this could be the solution ?