I wouldn't change the width of the tire because your messing with the original design of the manufacturer.
The better the quality of a rubber tire the softer the rubber and the faster they may wear.
What brand tire are you using. You may want to consider Continental tires. They are probably the best tire that you can buy but they are pricey. Another alternative would be polyurethane tires. They will last forever but they are really, really hard and will "flat spot" when the truck sits. They cause a thump until you heat the tire back up again.