The thing about in-line skates, for all their popularity, is that they’re so, you know, obvious. Not only that, but the beginner skater would be better off in “quads,” the kind of roller skates you haven’t worn since you chased your first crush around the rink at your 10th-birthday party. Not only are quads more balanced, they’re far more maneuverable – rubber bushings at the wheels (which in-lines don’t have) allow the skates to flex, which makes for quicker, more controlled turns. Still, in-line skating’s marketing juggernaut has almost nudged quads out of the picture. Where can you still find these retro wheels? “The only real skate shop left in Manhattan is Peck & Goodie 917 Eighth Avenue, near 54th Street; 246-6123,” says Harry Rodriguez, manager at Manhattan’s Roxy, where roller disco makes a triumphant return every Wednesday night. However, the place to buy roller skates may not be in a store at all. “Lezly Ziering has the best prices around,” adds the Roxy’s skatemaster. Call him at 777-3232 to place an order. An added bonus is that Ziering, the chairman of the beloved Central Park Dance Skaters Association, will not only sell you skates but will also – for a fee – show you how to properly boogie in them.