If you were running silver rims then I'd say ditch the black stem. But you're not, so the black stem should work with the black rims (and black saddle and black gear leavers). Black and white aren't really colours as such (they are achromatic colours) so you should be able to absorb as much of it as you like.
As it stands you've got pink, blue, black, white and a bit of silver, which is pretty understated in my opinion, so you probably could get away with gumwalls if that's what you fancy. In any case, it's looking like a well coordinated build.
NB. In light of the saddle being black, I'd be inclined to keep the hoods black but the bar-tape white - see the Concorde you cited at the start of the thread.
If you were running silver rims then I'd say ditch the black stem. But you're not, so the black stem should work with the black rims (and black saddle and black gear leavers). Black and white aren't really colours as such (they are achromatic colours) so you should be able to absorb as much of it as you like.
As it stands you've got pink, blue, black, white and a bit of silver, which is pretty understated in my opinion, so you probably could get away with gumwalls if that's what you fancy. In any case, it's looking like a well coordinated build.
NB. In light of the saddle being black, I'd be inclined to keep the hoods black but the bar-tape white - see the Concorde you cited at the start of the thread.