My bike has the wide whitewalls. Size on the rear is MU85B-16. These are equivalent to a 140 width. Not quite the 18" you're looking for but here is what the whitewalls look like on my FLSTC.
Richard - "Bikergeek"
2014 Street Glide - Color: Big Blue Pearl, ABS, Security System, Mustang Rider Backrest, Harley Davidson Standard Upright Sissy Bar and Backrest Pad
Last edited by bikergeek; 12-02-2012 at 07:42 PM.