Cadillac CTS First Generation Forum - 2003 - 2007 Discussion, How wide can my '04 CTS wheels be? in Cadillac CTS Coupe, Sport Sedan and Sport Wagon Forums; I'm looking into 18" rims for my '04 CTS. The rims I'm looking at are 18 x 8.5 and the ...
First, do you have the Sport Package or the Soft-Ride suspension?
Second, what is the offset of the wheels you are looking at? The "perfect" offset for 8.5" wide wheels is 42mm - anything around this range (40-45) SHOULD work, but then you have to worry about what tires you put on them. If you go with 245/40 you shouldn't have a problem, but 245/45 tires are "theoretically" too tall unless you have the sport/stiffer suspension. Some 245/45 tires are smaller than others, so watch out.
The offset is the distance from the center of the wheel to the mounting surface. What this means is that a greater offset (+45mm compared to +35mm) actually means the wheel sticks in farther. The smaller the offset, the more the wheel sticks out.http://www.usacomp.com/Offset.htm