There are 3,482 threads on tire size.

 

@SJkid 225/60R18 would be my vote. Having more information in regards to true driving needs could help in the tire recommending.

 

235/55-18 on 8 x 18 48 offset wheels look like this:

I've had them on for 2000 miles and have no regrets and no signs of rubbing. My calculation of the odometer and speedometer error effect is -1.5% (that is, now reads 59 mph at true 60 mph. the odometer already was -2.5% below the truth so now it's about -4%). My suspension is entirely stock.

 

235/55-18 on 8 x 18 48 offset wheels look like this:
My calculation of the odometer and speedometer error effect is -1.5% (that is, now reads 59 mph at true 60 mph. the odometer already was -2.5% below the truth so now it's about -4%).

The size of the odometer/speedometer effect with 225/60-18 would be roughly double that of 235/55-18 - the tire section height increase is 11.25 mm instead of 5.5 mm

 

Do you plan on changing wheels as well? If you don't change your wheels, you're limited to what tire sizes you'll be able to use.

 

For what effect? A fuller looking wheel well? Better grip? More sidewall flex...?