I am running a 130/60x12 rear, and a 120/70x12 front, so the Pirelli in the same size as long as they fit. (top of their line of course). And by the goose neck I mean the top of tube that the steering post runs through. I have seen this "mod" on SERIOUS race scoots., and have often wondered why it was done... I have found out why! The bars will oscillate with the tire. NOT A GOOD THING! I have highsided before, and do NOT intend to repeat. I believe even w/ a "perfect" tire/rim, the frame is design is weak in this area. For the 45 or so mph the scoot is built for, the problem will not show up. When you mod the scoot enough to exceed that, it does become a problem.