93 ultra classsic

My brother wants to put a car tire on his 93 ultra classic. What will he need to change to do this. I have a kumo on my 05 wing.
But that was pretty simple. We are taking a 6000 mile ride this summer. And he really wants go over. Please help.

Try this link

http://darkside.nwff.info/?p=tires

And this link

http://ejelta.com/tiresize/index.html?ws17=1&tiresize=180/55-b18&minwidth=160&maxwidth=205&minratio=&maxratio=&minwheel=5.5&maxwheel=&maxdelta=2

Didn't that model have a 140 on the back? If so, he'll need to carefully measure clearances available (by mm) and determine if the half-measure
will fit. Look up the "clay turd" trick for further info.