Just got a tire upgrade...

[zRobx71]

I just upgraded my tires from 275/60R20 to 325/60R20 and I was just wondering what are the negative effects of it. I checked rub and it's very close on the front of the front wheels and a little on the back of the front wheels. There is one issue though, when turned fully with power-steering maxed out it touches the steering arm. As long as I don't use the full rotation on the turn, it won't hit it. I've been reading about getting the gears switched because of power loss and MPG loss. When the 275's were on there it struggled between 4th and 5th gear when it came to an incline. Now it hardly ever gets in to 5th gear down the highway and runs about 12mpg instead of 16mpg like it did with the 275's. I don't know what gears are in there right now but I'm going to strongly assume that it's stock which I don't know what stock is either. It's a 2002 Dodge Ram 1500 4x4 4.7L btw. If anyone knows the stock ratio size I would be grateful to know for later reference. So should I spend the $1200-$1800 on a gear swap or should I just adjust my driving speed to get stock mpg's? I am able to keep it in 5th gear running 15mpg if I stay at 65-70mph instead of running it at the speed limit of 75mph.