Originally Posted by
cyccommute
If you have to inflate the tube prior to installation, put it in the tire first. That will constrain the tube to keep it from expanding too much. Every pressure vessel elongates as well as expands under pressure. Tubes just happen to be very weak pressure vessels that aren’t meant to be inflated outside of a stronger pressure vessel.
A rubber tube would expand and elongate much more than a TPU tube which isn’t very stretchy at all, contrary to what has been written above. The instructions on the TPU tubes say not to inflate them too much outside of the tire or the tube will be damaged.
Frankly, there is no need to inflate the TPU or any other kind of tube upon install. A tire that is tough to install will be harder to install with air in the tube. Just put the tube in the tire and mount the tire.
I put on my first set of TPU tubes yesterday. I already have some as spares on some bikes but I’ve never mounted them.
Based on this thread, I mounted one with as much air as I could do with my mouth, and another with no air.
Both went on ok. Kind of a pain, it definitely feels like mounting a grocery bag inside the tire. Thin. I would advocate for what your comfortable with and to go out of your way to do it without levers if possible.
Oddly enough, neither tire rolled evenly after inflation. I think with the less stretch in the tube, it doesn’t pop them into place. I got mine a lot better by manipulating the bead under about 3-4psi. I’ll revisit it later with some soapy water on the bead. That’ll fix it.
Funny thing about them, based on mounting them and fiddling with them, the spare in my saddle bag is butyl.
Im seriously questioning my other TPU tubes as spares, I just can’t really see a scenario where tubeless fails me that these would get me home. I’ll keep my sealant topped off and my plugs loaded.