Got some Continental PureContact tires a couple weeks ago to replace my worn out Sumitomo performance touring tires. Since I've not noticed a big diff in handling but the ride is smoother and my gas mileage has gone from 28 to 31.
Only one minor downfall is an I'd whirring sound at highway speeds. Not too hard to deal with but might annoy some folks.

 

They do make some noise on certain pavement types, especially grooved concrete, but I like mine and I did notice a slight fuel mileage increase too.

But that evened out over time, after 78,000 miles mine are just about used up, but I think I'll replace them with another set.

 

28 to 31 sounds more like you turned the defroster (AC) off.

 

What size? Continental's made in US?

 

215 50 17, made in France

 

I don't usually need to use it this time of year yet. I got the mpg figure on the same road, speed, etc. over 3 tanks of fuel. My car has always been consistent @ 28 mpg

 

The point is: most people have not read their Owner Manual and do not know that the Defrost mode and the ReCirc mode turn the A/C on with no A/C light. So, if you compare Winter (defrost) to Spring (fresh air) you will see a 2-4 MPG difference.

I have no idea if you fall into that category, but it sounded like the correct difference in MPG.