I currently have 285-70-17 BFG KM2's on my 2001 Super Crew 4.6 auto. I'm in need of tires and I'm looking at the Duratrac's in stock size standard load. They will be about 15 lbs lighter then the KM2's. I've always thought the truck was a dog and it has the 3.55 gear. Will the size and weight difference make a noticeable difference in acceleration?

 

You can't tell unless you do some before and after test that would show the change.
A 5300 lb truck with a 4x15=60 lb weight change is not very detectable.
It's a .011% change. Don't think you can detect that small a change..
You might try this, your tail gate weighs pretty close to 55 lbs. Take it off and run awhile and see if you feel much of a change. B honest about it.
I run an 02 screw 4.6 and don't think it's a dog at all at 261,000 miles.
Good luck.

 

I was thinking more along the lines of the tire mass and height making a difference in acceleration

 

A change in diameter by as little as an inch changes the final drive ratio to as much as 300 rpm change.
Tire pressure affects both rolling resistance and tire diameter.
There is not much more to it but tire construction and weight differences.
Good luck.
.

 

No, but with less unsprung weight, it'll ridemail a little nicer.

 

60lbs less to get rolling. That with the previously mentioned reduction in unsprung weight may provide you with mildly pleasant results.