1999 323i sedan

I have 225/50 R16 tyres and at low speed they seem to run rough and noisy. Is this normal? Should I go back to 205

a have a 2000 323i....with 225/50/r16....and everything is just fine!
what tires did u buy??? are they "w" rated????

Thanks for your reply
Tyres are Pirelli P6000
Fantastic to drive but noisy below 40kph