Good morning, I own a 2005 STR with the stock 18" wheels and tires. I also have a set of 17" wheels and winter tires from a 2005 S type. If the smaller 17" wheels will physically fit over the larger brakes, will the lager diameter (26.3" vs 25.6") cause problems?
I have read some of the threads on this subject but haven't found a conclusive answer. Can anyone help please?

 

I don't think the 17's are going to fit over the calipers ?

 

100% no

 

1000% nope!

 

Exactly, those Brembo calipers will chew up the rim...

 

the 06+ 1 piston are even worse because the bracket is so huge

 

Thanks guys, how about the other question? How much change in diameter is ok before there istrouble?

 

Just see how little room there is between your 17-inch wheels and the brake parts. You will find it is not much at all. There can also be issues with the parking brake cable on the rear wheels, that is again gets very close to the rims.
You need 18-inch wheels on an STR. (Or the 19-inch Barcelona wheels that were fitted as standard from 06MY onwards.)
You will also find problems with the offset that prevent other makes of wheels going on as well.

Mellow