Changing tire size and gas mileage/speedometer?

I just bought a 2000 toyota tacoma 2 wheel drive, it gets about 25 MPG. If I go from the standard 14 inch rims and tires to 17 inch wheels and tires will it effect my gas mileage and/or speedometer? and if so how much will they change?Changing tire size and gas mileage/speedometer?
go to www 10110 tires.com they show a calculater that compares tier sizes by dia circumfrence and revs. per mileChanging tire size and gas mileage/speedometer?
There's an equation but for the life of me I cannot remember it. Since you put smaller tires on from stock size, your odometer will read a few miles higher than you're actually going. The faster you go, the more it will be off. As for gas mileage, I'm not positive on the difference. Try calling a Toyota dealer and they should be able to tell you a little bit more.
call your local Toyota dealership and ask if the can recalibrate your speedometer for the 17'; tires that you want. they should be able to at little or no expense. another idea is measure the diameter of your existing tire/wheel combo and see if you can get a lower profile tire on the 17'; wheel to match the diameter. no change in size that way.
You'd get the best answer from a car technician.
No. You will not travel farther or shorter with different size tires. A mile is still a mile not matter what size the tire is.
YES YOU WILL CHANGE YOUR SPEEDOMETER AND GAS MILEAGE. YOU MIGHT GET LESS DRAG OR MORE DRAG. MESSURE THE TIRE'S CIRCUMFERENCE ON BOTH TIRES IF THEY ARE IDENTICAL THEN YOU MIGHT NOT CHANGE ANYTHING IF DIFFERENT THEN YOU WILL CHANGE BOTH MILEAGE AND SPEEDOMETER..