I finally squeezed a Shinko 230 150/90 -15 on the back of my S40. It did NOT just go on. I had to replace the side rail bolts with button head bolts and re-space the wheel and pulley. It fits under the fender, but not by much.( 6.25" wide ) With the Kaw. pulleys and big ass tire ( 78.25" circumference ) the odometer is now 23% off according to the gps.  Before anyone gets excited about such a big tire on a narrow rim, when I changed the rear pulley I installed a 3.5" aluminum wheel of a 02' Marauder so I could run tubeless. I was not happy the way the tire balanced at home and am thinking about using tire balancing beads to finish the job. I did a search about it and didn't find much. Has anyone got experience with using beads to balance a bike tire? They have glass, ceramic and plastic. I am leaning toward the ceramic after a few vids on UTube.
 On a related note, the bike seems happy now cruising at 60 at under 3400rpm. With one of Super Thumper's Harley mufflers I just love the way it sounds . A 55 to 70 roll-on is still reasonable in 5th, but I'm not trying to race anyone. If I cruse normal roads in the low 50's I am getting mileage in the mid 60's! With gas cheap now and retired, I am looking at some serious trips and mileage this summer.