At the risk of sounding stupid... Is there a performance difference between metal and rubber valve stems?

 

They don't flex around. So I guess the rim would be easier to balance at high speed. But I can't imagine it's significant. Need to ask someone who speed balances tires.

One issue people have had with the aluminum, is they can snap off.

 

The metal valve stems are part of the sensor units for the TPMS system, which intall onto the rims where normal valve stems would go in.

Probably about the only difference is that you won't have to deal with tire shops billing you for new stems when you get new tires put on.

 

SSR Comps come with aluminum valve stems. I thought he was asking about aluminum vs rubber. Although if the question was "why does tpms come with aluminum" it's probably to keep guys at tire shops from ripping them out before taking the tire off the wheel.

 

I've had valve caps with metal (brass?) inserts start to seize on the aluminum valve stem. I recommend sticking with caps which have plastic threads.