I was in K-Mart the other day and noticed they had Bell "universal" 26" bike wheel innertubes. I know there are universal bike pumps that are designed to fit both presta and schrader valves. However, somehow the idea of using one valve on an innertube to fit both holes seems deficient to me. Is the tube designed to fit both types of wheels? Has anyone tried using them? Would it be better just to get a presta or schrader only tube?