I just got a brand new rear Dunlop 739 for my bike and I have only 3 rides on it. Already the knobs in the center have started to round on the biting edge. I got the intermediate tire figuring it would provide good traction in almost anything and wear good on me. I have maybe 200 yards of slow push riding on the road. Would I have been better off with a soft terrain tire? What lasts the longest?