As the Delta wheels are only 5.5J wide you can fit 195/45 14 rubber, I have had that size of rubber on that size of wheel with no ill effects, BUT its not recommended by tyre manufacturers, they state that those tyres fitting range is from 6-7.5" wide.
Though just found this table
http://www.pneus-online.co.uk/equivalency-tables-advice.html that seems to contradict the info i saw before from Bridgestone.
Rim width Minimum tyre width Ideal tyre width Maximum tyre width
5 .0 inches 155 mm 165 ou 175 mm 185 mm
5.5 inches 165 mm 175 ou 185 mm 195 mm
6.0 inches 175 mm 185 ou 195 mm 205 mm
6.5 inches 185 mm 195 ou 205 mm 215 mm
7.0 inches 195 mm 205 ou 215 mm 225 mm
7.5 inches 205 mm 215 ou 225 mm 235 mm
8.0 inches 215 mm 225 ou 235 mm 245 mm
8.5 inches 225 mm 235 ou 245 mm 255 mm
9,0 inches 235 mm 245 ou 255 mm 265 mm
9.5 inches 245 mm 255 ou 265 mm 275 mm
10.0 inches 255 mm 265 or 275 mm 285 mm
10.5 inches 265 mm 275 or 285 mm 295 mm
11.0 inches 275 mm 285 or 295 mm 305 mm
11.5 inches 285 mm 295 or 305 mm 315 mm
12.0 inches 295 mm 305 or 315 mm 325 mm
12.5 inches 305 mm 315 or 325 mm 335 mm
But i'd say 185/50 is ideal size on a 5.5" wide wheel, with the ContiSports being superior to the Yoko's.