Last night I installed a set of S4 TII wheels with 205-55-16 tires on my 88 GXL, figuring they should fit perfect since it's a factory wheel with factory tire size.
Tires are Kumho MX if it matters.
I'm getting a rubbing sound from the left rear tire at times. I've inspected the tire to see if it was being cut by the wheel well lip, and it's not, no marks on the tire. There seems to be lots of clearance around the tire and wheel from the inside too.
Any ideas where the sound may be coming from? I had no issues with the factory GXL wheels and tires.

EDIT: forgot to mention the car has stock suspension

 

Some tire manufactuers make their tires slightly wider even though they state the correct size for your car.
I don't know why manufactuers can't aggree on correct sizes.

I was looking at some tires recently and I noticed almost a 1inch difference between a Bridgestone RE050 tire against a Toyo T1R tire. Same size 225/45/18. The Bridgestone was wider!

Maybe the Kumho is slightly wider... but it's definately a width-clearance problem...

 

Check the inside side of the tire to see if it's rubbing against the strut/spring or even your caliper flex hose.

 

I don't think the flex hose rubbing would be loud enough to hear in the car...

 

maybe it's those little nipple thingies that are on the sideway of new tires

 

I know when I had the stock muffler heat sheilds on it made a really loud rubbing sound. In the rear you can run 225's without rubbing problems.

 

hmm heat shields, good call, I'll check that since I know they are there.

 

Thanks for the tip, it was the heat shield, all fixed now!!