Troubleshooting Weaker New Trailer Brakes Where Adjustment isn't Issue

Ive read the answers on the weak trailer brakes. I installed new brakes on my trailer in 2019. Tow with a 2015 F-150 with factory brake controller. Have always set controller gain 2.5 empty and 5.5 loaded this year 5.5 empty 8.5 loaded. Had friends haul trailer said same thing theyve had to add gain to their controller when hauling my trailer compared to before. Checked all the wiring had on connection that was questionable, fixed it nothing changed. Took drums off cleaned brakes and adjusted the brakes. Only questionable issue is slight grooving in magnet contact on back of drum. I dont see that causing this issue of adding so much more controller gain. I manually activated controller on empty trailer with 5.5 gain, truck will take off after stopping while holding controller full power at 5.5, wasnt like that at 2.5 before.

asked by: Norman W