The size of the rim depends on what type and size of car you drive. Generally speaking, any car can be altered to use rim and tire of any size.
Without making any adjustments to the ride height or suspension mounting, different vehicles can accommodate different sized rims. Trucks and SUVs are able to accommodate larger rims. Most small to medium cars will not be able to fit anything larger than 24 inches into the wheel well. For trucks or SUVs, however, anything from 24s to 32s should fit in comfortably. It is advisable to consult a mechanic before making changes to the rim or wheel size.