I’m pretty sure standard tube valves/tubeless valves are brass (edited) and not alu. Peatys valves are alu and both front an rear sheared off in use on a mates bike. I’m guessing Aluminium is brittle, in a valve it’s thin, and the threads give nice stress risers for it to break across – you put a fair side load on them when fixing/removing a pump head. (that last sentence could be completely technically ignorant but aluminum doesn’t seem like a good material to use here).
i’ve various sitting around and no idea where each of them came from. Some have short stubby uppers, some have square bits that go into the rim rather than round, some have larger holes in the rubber bit. I just discovered the one I used in my new DT wheelset (which was OEM so came without valves) doesn’t seem ot have a removeable core (!?!).
IME you want
– square rubber block to go in rim
– steel tube
– big hole in the rubber block to make it easier to clear and give less air resistance for tyre mounting
– removable core.
What brnad meets those criteria?