The brakes are one of the few things that weren't stripped. It is just a single disc brake/caliper on the rear axle and then two discs in the front. I haven't done an electric ATV either before but have a background in electronics engineering so I am fine with the basics. From what I can gather, the speed controller I bought, a YK31C, has a two-pin connector for the brakes and when the brake lever is engaged there are two wires that go from it to the speed controller and send a signal that kills the power to the motor. I guess I might be overthinking it and that is enough to limit the strain on the chain/gear as it brakes, but I just wasn't sure. Electric motors have a lot of torque, I just didn't want to trash the chain and/or gear or damage the motor.