Understanding Wheel & Tire Sizes
The simplest way to buy new tires or wheels that fit your car is to look up the current ones and buy ones the exact same size. If you don't want to do that for whatever reason, you found a deal on craigslist on similar sized ones, for example, or you want to up-size your wheels for looks, it starts to get more complicated. I'll start by explaining the different important dimensions on wheels, and then move to tires. Wheels: Wheels have five important measurements: Image cortesy of sizeitup.com Diameter. This is the one you're probably most familiar with. It is measured in inches and is usually somewhere between 14" and 19". Width. Pretty self explanatory. This is also measured in inches. Bolt Pattern. This is measured by the number of lugs and the diameter on which they are drilled. It can be measured in either inches or millimeters. This is both important and difficult to measure. The easiest way, if possible, is to find out what car the wheels ca