James Alun wrote:
On overrun brakes vs electric brakes. Are electric brakes just on or off? The overrun brakes will apply more braking force the harder the towing vehicle is braking.
Nope, electric brakes require the tow vehicle to have a brake controller; this modulates the braking force based on the brake pedal position, simplying by varying the voltage applied to the brakes. There is an adjustment wheel or slider so that you can adjust this, very important. The correct setting for my dump trailer empty, will be grossly inadequate with ~5 tons in it... but running it at the fully loaded setting while empty, would see the trailer brakes locking up and tires skidding every time I so much as touch the brake pedal..
Oddly enough this controller has been an aftermarket thing in every truck/van I have ever owned, but not expensive or difficult as long as the vehicle already has the wiring and 7-pin trailer connector to support it.
One really nice aspect of electric brakes is that the controller will have a button to allow manual application of the trailer brakes alone. In a situation where the trailer is getting out of control and weaving side to side behind you, you may be able to recover by applying a bit of trailer braking, or by maxing out the trailer brakes in combination with more moderate braking from the tow vehicle. I am confident this saved my life on one occasion, coming down a steep hill with a very heavy load..
With that experience still a vivid memory after some years, I would never use overtaking brakes unless the trailer and load was very moderately sized relative to the tow vehicle..