It sounds like you took the truck in without a load, 75-80 psi is WAY too much air pressure.
Your sig doesn't say much, other than it's a F-250 XL. Is it 2/4 wheel drive? Diesel? Cab size? Bed length?
I cannot imagine you needing much more than 65 psi in the front, if it's a diesel.
The rears probably only need to be 40-45 psi unless you are towing.
New tires will squirm (my LRG's I have on now have been the worst of any tire, and where broke-in within 200 miles), having them over inflated will make the issue worse and make it last longer as tires need heat cycles to break-in and overinflated tires don't heat up as much.
I would let some air out, and drive it. If that doesn't fix it then talk to the place that sold you the tires. I would also have your aliment checked, but it sounds to me like a combo of new tires and too much air.
Just because they are rated for 80 psi doesn't mean you run them at 80 psi, over inflating tires effects ride, handling, wear, and increases puncture susceptibility.
To the people responding, read the sig. It's an F-250, they DO NOT come with P rated tires from the factory they come with E rated tires..
If you have 3 tires in 265/70R17 a LRB(P), LRD, LRE they ALL carry the same weight at 35 psi. The LRD and LRE carry the same weight at 65 psi.
This is from Toyo, other brands will be very similar.
http://toyotires.com/tires-101/load-and-inflation-tables
For reference the curb weight of a 2008 F-250 CC LB 4x4 Diesel is 7635, front 4756, and rear 2879. Lets assume some people, normal emergency items and gear. 4850/3100. That breaks down to 2425/tire on the front and 1550/tire on the rear. Now reference that Toyo chart.
The front's should be inflated to about 47 psi, so round up to 50. No more air is needed, maybe 55-60 if your going to do a long drive at 70-80 mph.
The rears are actually under the min load at 35 psi, so 35 psi is plenty for 1550 lbs/tire. I would run about 40 for high speed driving.
If the F-250 is gas, or smaller cab/bed, etc then those pressures will be lower.
