Does regearing after putting on bigger tires bring back some of the lost fuel economy as well, or does it just bring back the power?

 

depends on how you drive it but mostly power

 

When I went from 4.10's to 4.56's after installing 35's, it helped my mpgs because I could maintain OD when driving on the highway. This kept my RPMS consistently lower and saved gas.

 

Yes, it will help your mpg as well, however just remember that you're not as aerodynamic (or as light) as you were stock so its not ever going to be as good as it was.

 

How much bigger tires did you put on? over gearing can hurt mileage depending on how you drive.

I have a 4.10 gear set on 31" tires and my city driving mpg's went up, as it takes less throttle to get up to speed. It has also hurt my highway mileage. When I'm in a hurry and going 70 the 'puter reads 17mpg, but if I slow it down a bit to 60mph, I get back about 3mpgs.