Originally Posted by mstateglfr

Yup, ive pumped a 23mm tube outside a tire.
Yup, it get massive. Fat bike tire sized.
Nope, it shouldn't be something you use just to save a few bucks. If its all you have when you get a flat riding, sure. But there is no reason to seek out 23s for 40s (or bigger).
I used 40mm tires as an example, but bump it out to 2" 29er tires if you want. The point remains that there is a limit within reason.
There is no reason to overinflate a small tube just to make it large enough to fill the tire cavity when a properly sized tube is available.

My car can rev to 8000rpm and can go 130. That doesnt mean it was made to run for extended time at those limits. Hope you get the analogy.