I recently changed my tires and they do stick out of the fenders by a big ammount. It rains almost every day where i live and road debris on the truck is killing me. It has gotten to a point in which i need to clay the truck every 15 days so i bought a new set of fender flares. Lund RX310S which are similar to the riveted bushwacker.

The issue i have is that i do have a flare side box and i know that rears will not fit unless i do trimming on them.

This guy here did a hell of a job for his flare side but seems that is no longer around here
https://www.f150online.com/forums/20...check-out.html

Can any one give me any suggestions on how should i trim them, what tool should i use?

 

I would use a dremel with a cutting disk. That is what I used to trim the plastic valence on my truck and my brothers truck when installing brush guards and it worked great.