Long time ago I had replace the tires of my motorcycle with new.
The technician in the garage who installed the new tires in my aluminum rims,
he also replaced the valve stems.
Soon enough I realized that he did the mistake to add a new rubber valve stem at the front wheel ,
and a used one in the back wheel.
The one in the back wheel had signs that it would had an sort life,
even if I did complained about it, I got the classic answer, no worries it will last for long.
This was before two years time.
Even so I did search and buy from ebay ( USA) the best ones out there,
as long lasting high quality 3/4 inch short valve from Enkei ( 4$ its one) .
And I had them in storage for about two years.
Today I tried to inflate the real wheel and as soon I touched the rubber valve it broke off !!
and stayed in my hands.
I was ready to get mad, but them I said .. Thanks God that it did not happen else-ware than in front of my shop,
so to have more troubles , or even an accident in the street.
I just removed both wheels, and I have the new valves in my hands too,
all that I need to do is to wait few hours until the shops to open,
so to have them installed, I can no do it by my self, those tubeless tires are impossible, to come off by hand.
If you have any stories to share about those aluminum or rubber valve stems,
be my guest.