I haven't been able to find out what the diff is between rear rim widths (if any). I don't see any reason a 240 can't be used on a Touring,,,,,there is plenty of swingarm and fender clearance. I never understood the reason for the smaller tire on the touring....perhaps because it is de-tuned from the factory???? My bike had the METZ replaced at 7k,,,,but I didn't put most of the miles on and I have the feeling that it was rode hard and put away wet for the first 4k miles (judging by the skimpy center and the generous side tread
) I agree that how you ride and how you maintain have as much (or more) to do with tire life as the manufacturer of the tire. One of my buds has a fat ass wife (260+) and if he ran his street glide at tire spec he only gets 6-7k and thats without abusing the bike. He HAS to run it at 40-42psi to get any life out of it. He's happy when he sees 10k!!!