well bullagent, whenever you go with a wider tire you will also be changing the profile. because the profile is based on a percentage of the tread width
for example a 225/50-16 will be around 25" diameter
goto a 245/50-16 and you have around 25.8" diameter.
granted that 3/4" is not much difference but that is how it works
BTW a 245/50-16 is the max for a 7" rim and you will have to watch the tire pressure like a hawk if you want any kind of milage on a tire like that fitted to a 7" rim.