NEW GUY PC FL.

Hey all. new guy from panama city fl.
got a 97 f350 200k miles, daily driver but trying to lower and add rims, got some 19.5 with some 225/70/19.5 rims, how low can i go before i get into rubbing issues?

i am sorry guys, I am completely new to foum stuff, and about dumb when it comes to posting things, i can not figure out how to post pics from my pc here, i have done some serching for instructions, but i am failing! help....

my question....what size wheels are these?