Styling Rear right wheel grinding against mudguard

[FiatStilo2001]

So I recently changed my wheels from 205/55r16 to 225/40r18. After taking the old ones down there were small grind marks against the rear right mudguard, so I tightened the mudguard a little more so I didn't have to problem anymore.
The reason it is only the rear-right is because the rear-wiper fluid pump appears to be there.

All seemed to be OK but then I picked up some friends (2 in the back) and when I took my first turn I heard the wheel grind against it because it had dropped.

Have other experienced this problem? How did you solve it?

 

[portland_bill]

Sadly, I think your car is telling you the wheels are too big.

 

[FiatStilo2001]

I got some folks to get in the back of the car, I located the area of grinding, it was the inside. So I added 3mm spacers, and the problem is solved . Still odd it only occurred with lots of weight in the back.
Now checking if it can be lowered by about 30mm without getting other issues.