You have to consider wheel width too...depending on the width of the wheels you might be able to get away with a 45, but you'll want to consider keeping your speedometer as accurate as possible.
For example, I have 19x8 wheels and run 235/35-19 tires. Maybe in the rear I’d go to a 45, but I wouldn’t go to a 45 in the front because I don’t want to throw the speedometer off. The front of the car is the most important, since we drive front-wheel drive cars, which leads too...
Another factor to consider is the control arms, depending on the width of the wheel and series of the tire, you may have fitment issues there, as well. I could go down to a 225/35 up front, but then I’d have even less sidewall and cushion.
That’s the tricky part with a larger wheel setup. You have to make sacrifices…
Hope it’s not too confusing…
