Originally Posted by Drumnagorrach

It occurred to me that as nitrogen has larger molecules than oxygen and carbon dioxide,and that inner tubes leak the smaller molecules out through the rubber,that as the inner tube is re inflated over an extended period then the ratio of nitrogen ,to other gasses found in normal air, will increase and the larger nitrogen molecules don't pass freely through the inner tube wall.
To that end,does it seem to you cyclists out there ,that the longer an inner tube is in use ,the less frequently it needs to be re inflated ?
It may be my imagination ,but unless I have a faulty valve ,after the first few times I pump up my tires they seem to stay up almost indefinitely.
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