Remember that as the wheel size increases:
The wheel cost increases (on many wheels)
The tire cost increases drastically--especially when you get to 19s.
The change for cracked/damaged wheels increases (because of the loss of tire height between the wheel and the ground).
Besides, very few people will know she has 16s versus 17s or 18s. When they do notice, she is likely to be going 45 mph or more. Even then, those noticing don't even have the time to pull out a tape measure.
Buy her a real spare instead. Someday, you will need it.
The wheel cost increases (on many wheels)
The tire cost increases drastically--especially when you get to 19s.
The change for cracked/damaged wheels increases (because of the loss of tire height between the wheel and the ground).
Besides, very few people will know she has 16s versus 17s or 18s. When they do notice, she is likely to be going 45 mph or more. Even then, those noticing don't even have the time to pull out a tape measure.
Buy her a real spare instead. Someday, you will need it.