You just need to get it centered. You could whittle a piece of wood. The nuts and bolts keep it tight. So you could wrap a rubber strip around it to get it fairly centered. Then tap it into place.The key is get it centered. A good fit on hub helps to keep it from shifting up,down,back, and forth so the chain don't wobble off, curbs vibration and saves spokes. Use the bolts and nut to line sprocket so runs true. good luck.