The importance of tires is easy to understate, but there’s more to making sure your tires are roadworthy than giving them a swift kick. A wealth of information’s hidden in the alphanumeric mix molded into the sidewall of a tire. Jason Fenske of Engineering Explained is here to help you decode a tire so you can make sure it’s right for your application.
In this 12-minute video, Fenske walks through common designations on tire sidewalls. He starts by breaking down what is arguably the most important group of numbers, along with the one most people are familiar with: the size. Tire size is annotated with a mix of imperial and metric measurements along with a ratio to create a seven- or eight-character description of tread width, sidewall height, and rim diameter—all critical measurements when shopping for tires.
The second most important grouping is a four-digit string that tells the production week and year of the tire, which Fenske covers late in the video. This is especially important on hobby cars that don’t wear through tires at a regular rate. Rubber continues to age and harden with time, meaning that a tire with plenty of tread depth and no cracks in the rubber could still not be fit for road use. Knowing how to read this simple code will help keep your car safe, or make sure any used tires you might come across are worth the money.
This quick video will give you more knowledge about tire coding than you probably need, but that’s the best part. Be the life of your next dinner party discussing load rating and whether or not Susan should spend the extra money on acoustic prepared tires. Really though, knowledge is power, and all cars need tires at some point, so it’s worth it to brush up.