Re: BT-012 VS BT-012SS
Yup, me myself also use 190 for the rear. Did not worry too much abt the height though coz i use a 2mm shim to increase my ride height. The 954 calculated ratio for the increased height using shim is times 3. So i get 2 x 3 = 6mm. When the rear is brand new it is quite high, but after it worn dowm a little bit, it's all comes into place.
Looking at my buddies who used 180 on a 6inch rim, i saw the side wall of the tire is quite parallel to the edge of the rear rim. I think i prefer the 190 coz the tire edges stretches outside a little bit. Unless your 180 rear tire on a 6 inch rim is VERY sticky, then i think maybe it's ok. And to talk about spinning on the street when i dont want to spin, it's quite a handful, right?
Anyway, just my personal preferences, that's all. Everyone is free to make choices