My experience with a 190 rear -
I bought a set of Pirelli Supercorsa scrubs of my guy who deals with scrubs, grabbed what i though was my usual 120 SC1 front and a 180/55 SC2 rear, went home stuck them (i do my own tyre fitting) then went out and did a quick road test before my next trackday in 2 days. The bike just felt odd I went home, check pressures, checked suspension settings etc etc but never even thought to check the rear tyre size as i was convinced it was my normal tyre of choice.
Got to the track, 1st session out, siting laps done, time to hustle.............HHHHmMMm, odd, bike didnt want to drop in and turn as usual, wouldnt hold a line like usual, back into the pits and check warm tyre pressures, tyre wear, suspsion again - STILL not even thinking to check tyre size.
After 2 sessions a gave up, id lost all confidence in the bike and blamed the pain in my fractured ribs for putting me.
2 days later when wiping the rear wheel down i finally noticed the 190/55/17 marking on the tyre wall Pulled em straight off and stuck em on Ebay the only positive being that i made a profit on em
I wont be putting a 190 on the rear again thats for sure!!!!!