Is there any formula to use to see how heavy a trailer has to be before needing trailer brakes. I have a F150 and this question does not pertain to my boat trailer because its too small for trailer brakes (Tracker PT 170), but it pertains to a flat bed trailer that i have. Its a tandom axle 17ft trailer with a 3100lb max capacity. I haul hay, dirt, etc with it, should i get trailer brakes put on this thing. Its not hard for my truck to bring it to a stop unless really loaded heavy, but i also didnt want to create any more wear on my brakes than i have to.