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, H-D
Standard Upright Sissy Bar and Backrest Pad, Freedom Shield
8" Light Grey Shield, H-D Fork Wind Deflectors
Last edited by bikergeek; 12-02-2012 at 06:42 PM.