5 Ways to Find Your Car’s Tire Size

Finding your car’s tire size is important because it gives you a clear idea of the compatible and ideal tires for your vehicle. Tires significantly affect vital aspects of your car, such as safety, handling, fuel economy, and comfort. This is why using the correct tire size is crucial, as it helps maintain the careful balance engineers designed your vehicle with.

Knowing your car’s tire size is the primary basis for the tire specs you need should you require a replacement. Most services will ask for the tire size you want to buy. While you can also search your tire size by VIN and vehicle model, understanding tire size satisfies one of the most basic buying rules — it ensures you know exactly what you need and understand the product you’re buying.

Where to Find Your Car’s Recommended Tire Size

The first order of business lies in knowing where to find your car’s recommended tire size. Fortunately, many places and resources are available to you, many of which are conveniently located in your vehicle.

1. Tire Sidewall

Every tire has a code etched on its sidewall detailing its specifications. An example tire code is P225/55R17 or 225/55R17, depending on the tire sizing system. Each number on the tire code corresponds to a different dimension of your tire.

2. Online Search

Vehicle manufacturers also list recommended tire specifications on their websites. Make sure to search for your vehicle's exact model and trim level, as vehicle specs may vary between vehicle trims.

3. In Your Vehicle

You can also find the same information on many areas in your vehicle, such as:

  • Driver’s Side Door Jamb
  • Glove Box Door
  • Gas Tank Hatch

4. Owner’s Manual

Your owner’s manual contains the recommended tire size and other vehicle recommendations. You may also view a copy online if you do not have your owner’s manual.

5. Local Tire Experts

Tire specialists from a reputable auto repair shop like Caliber Auto Care have the experience and profound understanding of tire sizes and how they can affect vehicle performance. They understand which tire size you can use without significantly impacting vehicle performance.

Tire Size Explained: Decoding Tire Size Terminology

Tire codes can seem alien to novice car owners, but the truth is understanding how to read a tire size is straightforward. Each set of characters represents a different dimension of a tire. A tire code will typically look like this: P225/55R17. [link to Tire article]

The breakdown of the tire code is as follows:

  • P (Tire Type or Prefix) - The type of vehicle the tire is intended for.
  • 225 (Tire Width) - The measurement from sidewall to sidewall.
  • 55 (Aspect Ratio) - The tire’s height and width ratio.
  • R (Construction Type) - The tire’s internal construction type, radial or cross-ply.
  • 17 (Rim Diameter) - The diameter of the tire’s inner rim.

Factors In Determining Correct Tire Size Selection

Buyers must consider many factors outside of tire size when searching for replacement tires. The primary premise is that each car owner has unique driving needs and habits — by extension, each vehicle undergoes unique conditions. Tire buyers need to understand their specific needs to purchase a tire set that can deliver the most value. Some essentials to consider are:

Driving and Climate Conditions

While all-season tires are the best all-around choices, some tires are specially designed for particular road and weather conditions. Some examples of these special tires are:

  • Winter Tires - use special rubber compounds to improve traction, handling, and stopping at temperatures below 45 degrees Fahrenheit.
  • Summer Tires - are made of a special compound with a wider tread for greater road contact and improved dry road traction.
  • All-Season Tires - are tires that provide safe driving over seasons like spring, summer, and fall. However, they are not suitable for snowy weather and freezing temperatures.
  • All-Weather Tires - tires that are safe in any weather and road. They are stable on both snowy roads as well as hot, bare asphalt. They feature an asymmetrical tread design, specialized rubber compounds, and polished groves to grant them all-weather versatility.

Load-Carrying Capacity and Vehicle Weight

Tires also have additional designations apart from tire size and internal construction. A full tire code can look like this: P225/55R17 97V. The “91” refers to a tire’s load index, which represents the weight a tire can support when fully inflated.

The figure found in the tire is not a precise figure but rather a figure representing a corresponding weight in the load index chart. The example tire has a load index of 97, which translates to a max capacity of 1,609 lbs.

Performance Considerations

The “V” is your tire’s speed rating. It represents the top sustained speed at which tires can safely operate. Tires with a high-speed rating can handle the heat from high speed while providing ample control. Like the load index, speed ratings correspond to a specific value found in a chart. The example tire has a “V speed” rating, meaning it has a top operating speed of 149 mph.

How to Determine the Correct Tire Size for Your Vehicle

Determining whether your vehicle has the right tire size equipped is a simple yet crucial matter because it affects critical performance characteristics. Here’s how to check whether your vehicle has the right tire size.

Measure Current Tires

Measure current tires using a tire gauge and measuring tape, checking tread width, sidewall height, and wheel diameter. Compare these measurements with the figures found in your owner’s manual.

Interpret Load Index and Speed Rating

Check the current tires for the load index and speed rating and interpret them accordingly using their respective charts.

Account for Any Modifications or Upgrades

Once you have an idea of your tires' max load capacity and speed rating, make sure to account for any modifications or upgrades. Modifications can add extra weight to your vehicle, while some upgrades increase your vehicle's performance characteristics and can cause your car to run at speeds higher than the speed rating of your tires. Ensure that your tire operates within acceptable rating parameters.

Risks of Using Incorrect Tire Size

Using the wrong tire size will adversely impact your vehicle performance because it alters torque and driving force. This change in wheel dynamics often leads to the following:

  • Inaccurate speedometer and odometer readings.
  • Diminished handling, braking, and stability.
  • Worse fuel efficiency and uneven tread wear.
  • Safety risks (such as a sudden tire blowout) and corresponding legal implications.

Tire size significantly affects vehicle performance because tire sizes vary in rolling resistance, weight, and sidewall hardness.

Seeking Professional Assistance

The main benefit of seeking professional assistance is that they provide users with their experience and technical know-how. Tire specialists, automotive experts, tire manufacturers, and retailers are all reliable sources of information.

These credible sources will help you avoid misconceptions about tire size, ensuring you have workable and reliable information.

Proper Tire Maintenance

Installing the proper tire set is only part of ensuring optimal tire selection. Proper tire maintenance is crucial in retaining optimal vehicle performance and safety. Proper tire maintenance can be summarized in three key details:

Have Regular Tire Inspections

A regular visual inspection of your tires is vital because it allows you to identify and address potential issues if you experience tire failure. Consider asking our Caliber Auto Care technicians to check your tires for a more thorough inspection while you do your other maintenance tasks.

Observe Correct Tire Rotation

Proper tire rotation is a process that involves moving tires from one wheel to another. This promotes even tread wear, extending tire life and minimizing vibrations during operation. Correct tire rotations can either be a front-to-back or cross pattern. The best tire rotation pattern for your specific vehicle will always be the one recommended by your vehicle’s manufacturer. Make sure to rotate your tires every 5,000 to 7,000 miles.

Maintain Correct Tire Pressure

Overinflated tires are more likely to blow out because of the excess pressure. On the other hand, underinflated tires will not be able to provide the stability needed to support your vehicle’s weight, as well as the weight applied from cornering.

Vehicle manufacturer recommendations should be the basis for your tire pressure because it accounts for the weight of your specific vehicle and trim that tire manufacturer manuals do not. Again, refer to the sticker on the driver’s door jamb for manufacturer-recommended tire pressure.


Knowing the correct tire size for your vehicle is crucial because it significantly affects vital aspects of your car, such as safety, handling, fuel economy, and comfort. Using the correct tire size ensures your vehicle performs up to manufacturer specs and goes through the riding conditions it was designed for. It is one of the essential concepts that every car owner must understand if they want to make the most use and value out of their tires and, by extension, their vehicle.