These TPU tubes. There are no threads on the valve stem and no nut to hold it in place, at least the ones I’ve seen. I carry a CO2 cylinder and head for my road repair kit. How does that work? I road home on an almost empty tire the other night after flatting. I could barely get anything into the TPU spare before the cartridge ran out of pressure because the valve kept backing up through the hole in the rim and into the tire. If I’d had a pair of needle nose pliers to hold it in place …
And here’s a picture of my varicose TPU spare the morning after. What rubbish. Any suggestions that might alter my opinion of these things?
When I ran clinchers, I used Michelin tubes for a long time. Their valves were threadless. On installation or when I had a flat, I’d inflate the tube a bit with my mouth to help prevent pinching the tube while remounting the tire. Then I’d push the tire against the rim (or as much as necessary) at the location of the valve stem. I never had issues with the valve stem backing out.
My most-recent RideNow TPU tubes came with metal valves and nuts to hold the valve in place. It also has the right parts to install them into a tubeless setup if you want to do that (like those unbound setups with tubeless and tubes combined).
I don’t know what they’re called specifically but the plastic wedge that goes inside the rim and a rubber ring/seal.
Regarding that bulge, that’s common with TPU tubes. The RideNow ones specifically say not to inflate them outside of a tyre in the doco.
