I've had a set of Dunlop 235-75 SP-40's on my '73 S&S for ten years,and put around 2500 miles on them.Although they've mostly been light-duty miles @35psi front and back, and I've always garaged and covered my coach,I'm starting to wonder if it's time to think about new ones.The Dunlops look fine,but I don't really know from tires.Whaddaya think?