I already wrote that I did not read first post carefully.
Fitting 195 65 15 instead of 205 50 15 is OK- I thought he was gonna fit 195 65 15 instead of 195 50 15, that change is too much without further mods (e.g. speedo correction).
You can fit other tyres as long as certain aspects are within limits, i.e. the circumference is approx the same so that the travel for each revolution does not change too much, tyre and wheel size suit each other and the wheel [offset comes to mind] is not touching anywhere on the car on full lock and fully laden (or in case of rear wheels just does not touch arches), load index and speed index are up to legal requirement for the car in question.
That would not be the case for 195 65 15 if the original size tyre was indeed 195 50 15. For the OP's combination that is not true, as I have now said for the third time; he CAN fit it.
