This is the second time I've done this a what a difference . My door is 18' wide, insulated, heavy and was noisey as heck, squealing and squeaking when I used it. It has 3 cross braces and a few months back I noticed metal filings on the braces from the hinges on the door, I put a bit of syn oil on the hinges, did it again today and put a bit of oil on the wheels. WOW, what a difference its super quiet now.
Got a squeaky door? Give it some oil, you'll be suprised.
Finn