I'm going to approach this via complete idiocy: The wheel color are a very appealing and bold royal purple (meaningless to you). based on shitty googling:
http://www.colourblindawareness.org/...our-blindness/
http://health.howstuffworks.com/huma...blindness2.htm
I am assuming you have either Deuteranopia or Protanopia... Imagine the wheel's 'purple' to be a shiny and reflective version of yellow (based on shitty google, both forms of color blindness can still distinguish some shades of yellow from brown/blue/bleh).
in terms of dark brown (1) to neon yellow (10), I'd subjectively say its about a 7.5 due to the glossy coat finish. I think the wheels provide decent contrast via ultramarine (4) from a shiny perspective.
That said, I personally would not rock purple on ultramarine, but I think the others that previously voiced out would love seeing such a bold combo and would definitely go against the generic/norms of black/bronze/gold/etc.
Hopefully someone else here more skillful than I could photoshop the purple to an equivalent intensity of yellow so you can have a better idea of how purple-y it looks.
p.s. mount the suckers and post pics.