Here is my 03 EX on 17's. Not too big I could go up to 19's If I wanted.

I'm going down to 16's though. The thing I have learned is that in order to get the speedometer right, the tire must size accordingly to your stock steelies and by doing this, you will trade off smooth ride for exactness.
See if I can explain. The bigger your wheels are, the lower profile tire you need to exact your speedometer, the trafe off is that there is less tire between your wheel and the road and the bigger wheel you go, the more bumps in the road you feel and depending on the suspension the harder the ride. Not to mention that your more apt to bend the wheel on a speedbump or curb. My experiance.