need 18" tire diameter

i need the diameter for a 18" tire so i know how much to notch my frontier. Im not sure how wide of a tire im running but it wont be excessively wide, prolly a 225/35.

http://www.streetsourcemag.com/forum/topic.aspx?method=reply&topic_id=57856&forum_id=18&forum_title=&M=False&S=True

overall diameter will be 24.15" on a 225/35/18.