They're not supposed to be. You need to unscrew them and replace them with some new ones. You can send a complaint to your car-dealership, and they might replace it for you. (If they're not corrupt of course....)
Depends what tires they are because different tires have different densities...
Thousands of different car tires are made in America.
There are several different things that you need to think about. What type of driving are you going to do? What kind of vehicle do you have? All weather tires are a good standard tire. Performance tires are good for sports cars. All terrain tires are better for trucks.
rubber Rubber is used with many other things to make different tires, depending on what they will do, once on a car.
I would NOT recommend buying tires online ! -You want to physically see what is going on your car. Your life will depend on it.
Conduct and experiment to rest the trip of different tires
Conduct and experiment to rest the trip of different tires
yes, it is not recommended however. The safest thing to do is have all four tires be identical (same brand, tread pattern, speed rating, load index). At least if you are going to mix and match change the tires two at a time.
Radial tires are made specifically to reduce the wear and tear of your car whereas goodyear tires are simply regular tires.
Tires have different rolling resistance. One of the fromt must have a different rolling resistance one way but not the other. As long as it is going streight it is ok.
If the overall height is different, then yes.
The front tires move when you accelerate a front-wheel drive car, while the rear tires move when you accelerate a rear-wheel drive car. All-wheel drive cars have power going to all four tires when accelerating.