If you are looking around the market for new automotive tires, all of the different tire specifications and the technical jargon you might hear from tire salesmen of various tire brands or other “experts” might confuse you and make your purchase rather intimidating. The only way to fully understand the general tires out there is to read up about them and try to understand the concepts at work, the significance of all of those sidewall markings, and any other information you can get your hands on.
For example, you may have been at your wit’s end as to how a car tire with 30 pounds per square inch (psi) of pressure can support such a large car. Well, the next time you get in your car, look closely at the tires. You will notice that they are not really round. There is actually a flat spot on the bottom where the tire touches the road. This flat spot is known as the contact patch. If you had been looking up at your car through a glass road, you could measure the size of the contact patch. You could have made a pretty good estimate of the weight of your car, if you measured the area of the contact patches of each tire, added them together and then multiplied the sum by the tire pressure.