I run the plain jane rubber ones on my cragars, never had a problem. My father originally ran nice chrome bolt on valve stems on his cragars, never had a problem with them loosening up or the caps seizing to the stem. However even when properly torqued as per the instructions, I noticed the rubber seal on the outside lip of the wheel was distorting. I backed them off a bit and after a year the seals just rotted away and it started leaking air. His is a dd, no wheeling or anything. I switched em back to rubber for him and he hasn't had a problem since. The finish also looked pretty crappy after a few months too.