Yes, the engine will have to work harder to turn them
Yes, the tires will ruin your gas mileage overall. Bigger tires weigh more and they're harder to rotate on the vehicle even though they gain greater traction.
My research has shown that if you don't add bigger wheels and tires the gas mileage will stay about the same. Maybe at worst you might lose 1/2 of a mpg.
No it will hurt your mileage, handling, braking, ride, and your speedometer will not be accurate. Stick with the OEM size tires that came on your car.
Yes.
yes
Yes, in fact, rotating and replacing tires regularly is essential for maintaining your car's optimum gas mileage.
No.
Keep them properly inflated and balanced.
incorrect tire inflation
It lowers your mpg
I do oil changes and to make sure all tires are the the right pressure, if tires arent right pressure you lose gas mileage and regular oil changes and rad flushes.
You will get the best gas mileage if you get the tires that fit your car that have the least rolling resistance. Rolling resistance is the amount of force needed to keep an object rolling at a constant speed. Heavier tires and those with deeper treads are less efficient. Remember to properly inflate your tires too.