are you talking about CF wheel . I have 18 " wheels you can fit 240/40 18 R and 130/70 18 F ,The rear will be the same diameter but the front will be 4.9% smaller and the bike will sit 16 mm lower on the front. or you can try at 140/7018 inch but I think you only comes in H speed rating and its 2.8% smaller diameter and the bike will sit or 9 mm lower.
I believe ponters has the sizes you mention and abs seems to be working okay