My 1993 VN750 still has (I am pretty sure) the original Dunlop Qualifiers both front and rear. At 7500 miles, the front is down to 1/32, the rear to 4/32. Very minor cracking on the front, none visible on the rear. Both hold air no problem. This begs several questions. Should I replace them with radial or bias ply? Obviously, like a car, you should do both, and not mix them? The front Dunlop is a ribbed tread pattern. The catalogs don't show much available in a rib. The rear looks a little more aggressive, but the new stuff all looks very treadless, with a few scores for rainwater runoff. So, what is the wisdom of the website? I am a casual rider who just likes to cruise around, not a USGP hot shoe, so I don't think I need the latest and greatest. For that matter, why shouldn't I just replace with exactly what came with the bike new, assuming they (or something close) are still available?