Like the Rim diameter this is another crucial factor depending on which you might want to select Alloy Wheels for your car. Each Alloy wheel may come with different width. This width decides the tyres compatible with the alloy wheels. The Rim diameter is also crucial as if you put rims which are very wide then the tyres that go with it will also be very wide. Wide tyres in small cars happen to touch the fenders while turning or sometimes even touch the braking system.
When you are changing your alloy wheels and along with it if you want to increase the tyre width then choose this option. Most of us like chunky heavy wheels on our cars. Fatter tyres give more grip to the cars. So in most of the cases they may increase your accelaration and give better breaking. However this is at the cost of reduced milage.
While buying alloy wheels be careful that you dont exceed the width too much. In most of the case increasing the with by more than 2 or 3inches may create crlearance issues. We would also suggest you to try turning the wheels completely left and right after installing the new wheels. This will let you know the kind of clearance that you getting.