If you want a largish bicycle, you're probably thinking of intarsia, where the knitpro chart would be great. I'm not sure about fairisle, I don't recall seeing anything like that done before, would be really interested to see how you went with that! Actually, I don't see why it wouldn't work for FI/stranded knitting too. Remember you need to select the knit-shaped stitches, as they aren't square, and that an image in FI may look jagged at low-res, so if you have trouble with it looking pixellated, a bigger\more stitches motif may be better?
Sounds interesting, please keep us updated!