Just a quick word of warning about alloy tyre valve caps.
DONT USE THEM
Had mine on for a couple of months and went to take them off to check my tyre pressures, the bugg*rs wouldnt come off, I tried everything wd 40, Brute force , heat ,nothing would shift them, In the end i had to get the Dremmel out and cut them off.
So if you have got them, check that they can come off and bin them.
You cant beat the black plastic ones anyways.