So I’m short on tubes, and I’ve got a few front wheels, none of which are going. One has two mystery flats in a row, but it’s the wheel I want to use. I’ve got an otherwise good tube and tire in another wheel I’m going to use for now, but I snapped off part of the valve and it won’t work properly. Can I just pull the valve core out of the mystery flat tubes and install it into this one?
i’ve done it before. on both presta and schrader. inflate the tube off the rim to make sure its the core though.
You can definitely do that. It’s fairly straightforward and you can probably figure it out by looking.
i’d say about 3/4 of the presta valve tubes i have do not have a removable core- i.e the presta valve is all one assembly
sample size about 25 tubes
see on this one how there are some little flats machined into the silver part of the valve?
with a crescent wrench or even a pair of pliers you can unscrew the valve core from the tube.
here’s a picture of a presta valve with a non removable core:
The only presta valves I’ve seen with removable cores were on slime-tubes
I thought they were all removable… 
I have a few that are removable, and all of my tubes are qbp generic and Kenda, as far as I know. Checked today at the shop and our qbp generic tubes don’t have removable cores. I guess this means the Kendas do? Or maybe I have some third kind of tube that I don’t know about?
I have some tubes that had removable cores (aside from my tubulars)… I think… THINK, they were/are specialized??? Anyone at a shop confirm/deny? They’re all in mah wheels.
specialized tubes do have removable cores.
i wish! pain in the balls when i’m trying to find something to work with valve extenders. none of the cheaper michelin ones do, the vittorias do.