Schwinn World's of that era had steel rims. Do you have steel rims [MENTION=543486]aaroninternet[/MENTION] ? If so, upgrading to a better, aluminum rim wheel set will be a big improvement. You may want to keep an eye on the width of the hub. I think yours will be 126mm. You could get wheels with wider hubs, which will require you to widen the space for the hub to fit. This is do-able on your bike.