Rims come in multiple sizes, usually expressed by their diameter. Two of the available sizes are for wheels that are 14 inches across and wheels that are 15 inches across. Technically speaking, the difference between these two rims is one inch, but that inch translates into differences in cost and style.
Rims are made of expensive metals and alloys. This means that the bigger your rim, the more metal it uses, and the more expensive it will be. The larger rim size also translates into larger tires, which means more expensive tires.
The size of the rim will affect how low to the ground or high your car rides. This is a choice of style that every car owner has to make for themselves. In the context of 14- as opposed to 15-inch rims, the difference is not very noticeable, unless the one inch is the difference between the car scraping the ground or not, or the tire fitting into the wheel well or not.
When it comes to tire size, you need to make the stylistic decision between thick tires or thin tires. If you opt for a thinner tire, then you have more space in the wheel well for a larger rim. The thinner tire will also visually emphasize the size of the rim. If you were looking to have a thicker tire, and the corresponding improvement in traction with the road and handling, then you would need a smaller rim so your tire can fit in the wheel well.
