Today let’s look at how to quickly find the correct size tire for your vehicle while also helping you understand what exactly those codes on the sidewall mean. It’s always nice to have some deeper knowledge, plus, it’s possible you may be looking to expand your vehicle’s “shoe” selection. Let’s dig in!
Treasure Map: Your Vehicle's Information Sticker
The most reliable place to find the original equipment (OE) tire size, the one recommended specifically for your vehicle, is the sticker located on the driver's side door jamb. So, simply, open your driver's side door and look around the frame, and you'll likely find a white or yellow sticker containing a variety of important information about your vehicle, including the recommended tire sizes (though rare, some vehicles have different sizes in the front and rear) and inflation pressure. Snap a quick picture of the sticker for reference and you’re set!
If, for whatever reason, the sticker’s not there, you can also find this information in your owner's manual. The manual might also offer additional details or even alternative tire size options. Later we’ll get into things to be aware of regarding changing the overall diameter of your replacement tires, if that’s something you’re considering, but first, let’s break down tire codes.
Decoding the Sidewall Cipher
When looking at the sidewall of your tire, you'll see a series of numbers and letters, these provide crucial information about not only the tire's size but also its capabilities. For most passenger vehicles, the tire code follows a general structure like this:
[Optional Letter] [Three-Digit Number]/[Two-Digit Number][Letter][Two-Digit Number] [Two or Three-Digit Number][Letter]
That may seem like a lot, but let's break down each of these components:
[Three-Digit Number] - Tire Width:
[Two-Digit Number] - Aspect Ratio:
[Letter] - Construction Type:
[Two-Digit Number] - Wheel Diameter:
[Two or Three-Digit Number] - Load Index:
[Letter] - Speed Rating:
For owners of high-performance vehicles, understanding the speed rating is particularly important to maintain the car's intended performance and safety characteristics. Again though, always consult your vehicle's owner's manual or the tire information sticker for the recommended speed rating.
Why Sticking to the Right Size Matters
If you’re considering changing the look and/or characteristics of your vehicle with smaller or larger tires, there are important things to consider:
- Accurate Readings: The original tire size is calibrated with your vehicle's speedometer and odometer. Smaller diameter tires will make your speedometer read higher speeds and, naturally, larger tires will cause it to under shoot your actual speed.
- Optimal Performance: The manufacturer designs the suspension and handling characteristics of your vehicle around a specific tire size. Deviating can negatively impact braking, cornering, and overall ride quality.
- Avoiding Mechanical Issues: Incorrectly sized tires can sometimes rub against the wheel wells, suspension components, or other parts of your vehicle, not to mention potentially causing your engine and transmission added stress by either fighting extra inertia of large tires/wheels in the low end, or revving higher in the top end to cover extra ground with smaller tires.
- Safety: Finally, using the wrong size can potentially compromise the safety features of your vehicle and the tires themselves. Be sure to do your research before drastically changing tire sizing, as you could find it to be more of a project than you initially thought.
While there might be very slight variations in tire sizes that could technically fit your vehicle, it's always best to consult with a tire professional before straying from the manufacturer's recommendation. Should you have any further questions, we’d be happy to help, just remember, keeping your vehicle’s "shoes" the right size will ensure a safer, smoother, and more efficient ride!