My daughter has 205/60R16 on her Ford Taurus, the tires should be 215/60R16, the only problem is that the speedometer reads about 3mph faster than actual, but that's ok, if you're in a 65 zone and the speedometer shows 65mph a cops radar will only show 62mph (cuts the chances of getting a ticket)

The Speedometer will read faster then actual, but really they're not that accurate anyway. The odometer will register more distance then with the taller 225 s ...the tires don't carry the same load, You don't say what car you have, so you'll need to find out if that's an issue, and if the air pressure can be increased to safely carry load...some you can some no...and some tire shops won't install a smaller tire...

There is hardly any difference between these two tire sizes.

225/70/15

8.86" Wide

6.20" Tall

215/70/15

8.46" Wide

5.92" Tall

The 225 will be 0.40" wider and 0.28" taller.The height measurement is called the aspect ratio and its the height of the sidewall basically.So in otherwords,the 225 sidewall height is only 0.28" taller than the 215 sidewall height is.

Smaller circumference tires will make the speedometer read inaccurately - faster. Smaller tires will have a LOWER load carrying capacity.

If you have a front-drive vehicle, you're screwing up your suspension geometry: if you're lucky, you'll only veer off to the side.

Why would you do this, anyway? "Save money"? Stupid idea on something as important as tires.