Chainline & indexing arn't affected by the change in wheel diameter, but by the likely substitution of an "ATB" wheel, dished and spaced for a chainline of around 47mm for a "road" wheel, set up for something like 43mm. Probably not enough difference to be a showstopper but the sprockets are likely to be in different places and the drivetrain may not quite work quite as well as it should.
> Buns has got the right drift, but the figures he gives are for the diameter of the wheel, not the radius...
Those would be the figures I'm dividing by 2, would they?
622-559 is 63mm, by my calculations. Curiously, that's twice 31.5....
Would it be possible to run 26'' wheels on a 700c frame?