I have a 180/55 on 6" marchesini n the rear and 120/60 in the front. A little adjustment to the preload is necessary to dial it in. I love the way it handles now. My bike is a 93 900sssp(at 350lb) and it has the same swingarm as yours. There is no clearance problem with the swingarm. The chain rubs a little tiny bit but its probably due to the 6" wheel.