there would be many ways to multi colour one, to start u dont have to dye the hole wheel at once, do sections at a time, the colours would possibly blend in
im doing sum research now bout ways used make hippy shirts did once back at school it possible would work, it ws just a suggestion i will try it later, but yeah as seems the dye soaks into the PU as you all ride them & the colour is just not on top it has been absorbed by the PU material,
then indeed u could soak a section at a time, & it hopefully would mix, i will try one later when i do a few wheels ill try one or 2 with a few colours from the others i dye complete one colour that way u can try not wasting a pack of dye just try multi colour one & it stuffs up