The tread is the area where the differences start, the compound is high silica for all wet and dry grip and formulated to be stiffer to reduce tread squirm. Silica makes for a more nappy surface which especially helps wet grip. The tread pattern is particularly designed to enhance grip in the rear of high powered cars. The twin center ribs are particularly good for this. 4 circumferential grooves with shoulder exit grooves help eject water from the contact patch to improve wet handling.
The outsides of the tread have large tapered blocks; the large blocks are stiffer and have less tendency to squirm while the tapered grooves won’t squeeze down under load. This improves both dry and wet performance. Finally, the sidewall near the shoulder and the shoulder tread blocks are reinforced to reduce squirm, to improve dry handling while the increased stiffness helps keep the grooves open to improve wet traction.
The fit of our wheel/tire combination was great with plenty of room for our big Stoptech brakes as well as a lot of room in the wheel well even though the WRX has smaller wheel wells than the STI and we were sitting about 2″ lower than stock in ride height. Here are the front wheels of our car.
The same is true of the rear, the rear Stoptech brakes fit easily and there was plenty of room and zero rubbing in the wheel well or up against the fender.
With the exception of the paint, Ian’s car is looking pretty good and sits really well. The wheel’s styling match the car perfectly making it look like a rally car in tarmac trim!
There is enough side clearance in the wheel wells for absolutely no rubbing without any sort of messing around with cutting or rolling fender lips and heating and bending wheel well liners. We think a 235 could still fit in here easily and a 245 might work with a little massaging.