If you change your tyre size without switching out the rear end gears to compensate for it, you'll run lower speeds at higher RPMs (which gives you more pulling torque, but kills you on mileage and overall top speed), and your speedometer will show you going faster than you actually are (unless it adjust it to compensate for the smaller tyres).
get smaller tires
oyeah it will
If the truck is in 4 wheel drive mode, yes.
Smaller profile tires should not affect the anti-lock brakes, but will probably affect traction control.
Putting on any different height tire will affect the speedometer somehow.
The 2002 on up truck has had a 17 inch tire and wheel option.
You can find many good deals on affordable truck tires at: www.ebay.com
Yes, all vehicle tires have treads on them. Truck tires will usually have larger and deeper treads than regular sedans.
You have a few choices for truck tires online. I would go with www.DiscountTire.com .
When you are shopping around for truck tires, there are a number of brand names out there that will be vying for your attention. However, with the high cost of truck tires you really should take the time to look into generic truck tires as well. Not only are these tires often comparable in quality to their brand name cousins, but they are a fraction of the price. Since these tires are so expensive, every bit helps.
If you need a really big tire for a big truck or to raise a smaller truck off the ground higher then super swampers are a good buy depending on where you purchase them.
Wind currents from the vehicle can affect smaller vehicles around them, yes.