Just as a point of reference.... Changing the wheel diameter will in no way affect braking.... changing the tire diameter changes braking.
A little clarification on what I posted; I was more meaning about the additional rotational mass of the 20" wheels, rather than a change in diameter. Those 20" wheels, especially the cast aluminum ones, are much heavier than the standard steel or even a stock size aluminum counterpart. The additional weight will effect braking.
