Ok so hi my name is John and I own and love my 2004 F-150 its a V-6 and has been great to me since I bought it from an older gentleman in N. Jersey about 5 years ago. Outside of routine maintenance I have had to do very little to keep my truck running great. For christmas my wife gave me 4 new tires. They are good year assurance cs fuel max tires and they are size 255/70R16 and they are one size bigger then my previous tires were. The tires look great on my truck and my wife got a great price on them at just over $100 each through our friend who is a good year employee. Here's the rub, since installing the new tires I have vibration in my truck. Originally at 60 mph now it's around 70ish. Is this normal? Do tires require a break in period? Were they not balanced properly? Is it the size difference? Looking for help in Philly please.

 

Probably just not balanced right. There is no break in period for tires. When I replaced my tires/wheels, I used dyna beads. They work great and never have to rebalance them ever again as they are continuously self balancing. I use them in my motorcycle tires as well. http://www.innovativebalancing.com/
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It's because they are goodyears.

 

Goodyear tires are no worse than any other brand, they all have good and bad ones. I use to run Goodyear tires exclusively for years, just happened on to a great deal on the Coopers and couldn't pass it up.
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Last 3 sets I have had were garbage. Got 25k out of the set on my truck and they were completely shot. The wife's grand prix got 40k and the same old crap. Feathered, loud, and cracked. I will never have another set in my driveway.