SHELBY GT 350 Member
Joined: Jan 2011
Location: Central Massachusetts
The best way to do this is to go by the tire manufacturer's specifications for wheel width.
Look up the tires you are considering on Tire Rack or some other source that has the specs; go to the "specs" tab, and look at the recommended wheel width. If 9" falls into range, you are OK. If not, try a different tire size until it comes out right.
For most responsive handling, you don't really want the widest possible tire on the narrowest possible wheel; better to stay toward the middle of the range.
| 2010 GT coupe | Daily Driver with some Steeda and GT500 take-off stuff for the occasional track day