Just wanted to add, that changing tires out of nominal size doesn't affect ABS (first version at least) at all. Today I had to install what I found on local market (mine tires where totally trashed):
130/70/18 on the front - feels normal, bike became more steady especially in turns, on old stock size tire I had to catch it from diving into turn.
when I installed 150/70/17 on rear - rear end of bake started to feel light and fidgety in turns. Didn't like it, going to replace it to 170/70/17 next year and leave front as it is. I found 170/70/17 more comfortable and interesting in steering in combination with 130/70/18 on the front.