The abve is true, this is because all wheels with a half inch, ie: 14.5, 15.5, 16.5 etc have a tapered seat for the bead, where as standard size, 15, 16, etc have a seat that is 90 degrees. this is why you can't put a 14.5 tire on a 15 inch wheel. It will fit, but go to air it up and...BOOM. I've seen this happen at the tire shop i used to work at. but this tapered seat half inch wheels and tires have, is what makes them so you can't air them down.
later, Jaron