Motor braking.

[Serum]

You can use the motorbrake, but the heavier the vehicle, the harder it is to brake.

the motorbrake means more stress on the controller, and the motor will heat up sooner. What it does is 'shorting' the wires of your motor, and the energy is stored back into your cells. (tipical way of braking with electric motors)

Most controllers can handle it though. If you tell us the setup you want to use, we can tell you if it's wise to use a mechanical brake or not.