When you replace your current tires and wheels with bigger tires and wheels your speedometer will read slower than what speed you're really traveling down the road at.
So while your speedometer 45 MPH then you're really likely going down the road at a speed of 60 MPH so it can make it easy to get a speeding ticket when you think you're actually going the speed limit.
Larger tires can also decrease your fuel mileage as well so be aware of that.
If you do put larger tires on your vehicle you'll need to watch your speed and factor in the speedometer reading a bit slower than what speed you're normally traveling at.