The only time I had an issue (with 16" Michelins) was when I didn't get the rear one shoved firmly under the rear tire. When I went to back off the rear one snagged the front tire a bit. No harm, no foul. I may trim off 1" or so, but I am not sure it is necessary, yet.
"If the women don't find you handsome, they should at least find you handy." - Red Green