Weather's better?
Okay maybe AND it's still light at 6.15pm - when do the clocks go forward?
As to your Question in title.
Recall 170 section was o/e and 180 was widest fit - even if 190 was able to squeeze in, too wide for rim with wrong profile.
i used to run a 190 dunlop 208r on the back of my 89 exup, never had a problem with it, the only real difference i found was in very tight twisties where it was a little slower responding but in straight line and sweeping/a road twisties it was super stable and felt more planted