I got a nice set of used Volk GR-C wheels, but the valve stems that came with them are no good, and need to be replaced. However, the holes in the wheels are tiny as hell, and no tire places in my area have stems that will fit. I tried on the internet too, no luck. The holes look to be about 6mm. (need ruler to be sure) The stems looked pretty good, they were a thread locked type instead of the typical rubber crap.

Any ideas?