I have recently gotten a hold of my wife's old Schwinn Pixie from when she was a kid and learned how to ride a bike on it. The stem is seized to the fork and I cannot replace the headset bearings but they seem to be okay and will do for now. The bottom bracket ones could stand to be replaced as well but that will come at a later date. The only thing stopping me from getting our kids on it, is that the front hard rubber tire is missing. The rear one is intact and seems to be good. I would love to find a replacement for the front to have it original, but I know it will be a rough ride for the kiddos. My main question is if I want to replace both front and rear rim/tires, what size is going to fit? The rims themselves measure 13" and the tire on the rim has a total outside dimension of 16". Will newer rims and tires from a 16" bike fit on the Pixie or is this going to be a special order item?