wheel fender rub

[echocluster]

my z has had this problem since i bought it. the wheel rubs on the fender when i am going fast and hit a good bump. it is worse when i have another person in the car. i thought the springs were weak so i got new ones. now thw problem is not as bad but it still happens. the springs lowerd the car by one inch. i have heard offset being thrown around. is that what might be the problem? my rims are offset too much? can i fix that with spacers? wouldnt spacers push them out further and make it worse? or could it be something else?

[MikeW]

What size wheels and tires are you running? That's the key here.

[echocluster]

the rear rubber is p215/60r14

the rims diameter from flange edge to edge is 15 1/4 inch and is about 7 inch wide