anyways heres a simple calculation that can help

your tires WERE 175/70/13 and you went to 195/50/15

so heres what you do, convert 175mm to inches (175 x 0.039) = 6.825inches

then multiply your inches by 0.7 (the 70 shows that 70% of the width of the tire is the height of the sidewall) 6.825 x 0.7 = 4.7775

then you multiply that by 2 and add the 13 inches for the rim and you get the wheel height. (4.7775 x 2) + 13 = 22.555

so do the same for the new wheels and you want to be as close as possible.

195 x 0.039 = 7.605
7.605 x 0.5 = 3.8025
(3.8025 x 2) + 15 =22.605

so 22.555 compared to 22.605

you went a little bigger by 0.05 inches, which means that your speedometer will say you are going slower than you actually are (but in this case i doubt it will be noticable)