I have a 98 1500 vulcan classic and I am looking for tires for it. My main conser is whether I should buy bias or radial tires for it. the one bike shop in town thats is not a dealer says I should use bias, but when I ask why his answer was they did not make radials in that size ( and he's kind of a buthead). the tire on the back is a Michelin Commander, of which the only one I found online like it is a radial. so which should it be?