Oh boy!
Well maybe; what are the tire heights, or the exact sizes?
And did both tires spin before?
a 195/70-14 is about 24.7 tall
a 225/75-15 is about 28.3 tall
for a difference of 14.5% which would be like going from 3.23s, to 2.76s.... so I mean it's possible.
BTW;
If only one wheel spun; and you have an open differential, this action makes the tire spin at twice the indicated speed on the Speedo. This often cooks the gear oil and welds the spiders to the crosspin, making it a poor-man's posi.
But, you will lose the differential action which will suck power on every turn, and; if the two rear tires are not equal in roll-out, this will suck power too, and one of them is gonna wear out prematurely.