Hello
I believed that an important thing here is the load index of the tires. In my owners manual (car bought here in Finland, which belongs to EU) following tyres are recommended:
195/65R15 91V
205/65R15 94V
225/55R16 94V
235/45R17 93V
Lowest load index here is 91 which means (table found in internet) 615 kg/tyre. According to the owners manual max axle loads are 1080 kg in front and 1155 kg in rear. Seems to be logical if I understood it correctly. So perhaps the tires with too low load index are not safe.
On the other hand that size seems quite big in diameter (if my calculation is right, usually not) about 686 mm while your 225/55/16 are about 654 mm. If there is space enough then they can rotate; how about ABS or TC when there is diameter difference between front and rear axle? However, I prefer to have winter tires in all four wheels (and with spikes in Finland, too).
195 205 225 235 215
65 65 55 45 65
15 15 16 17 16
381 381 406,4 431,8 406,4
634,5 647,5 653,9 643,3 685,9