What are my tire specs?
Your tire specs tell you the size, load rating, speed rating, and inflation guidance. The most important details appear on the tire sidewall and on your vehicle’s door placard.
Understanding these numbers helps you choose the right tires and maintain safety and performance. Here’s how to locate them and what each part means.
Where to find your tire specs
Use these sources to locate exact specifications for your vehicle’s tires before buying replacements or performing maintenance.
- On the tire sidewall: read the size and markings printed into the rubber, such as 205/55R16 93V.
- Door placard (driver’s door jamb): shows the recommended cold inflation pressures for the front and rear tires and sometimes the preferred tire size.
- Owner’s manual or tire specification sheet: lists acceptable tire sizes, load ratings, and inflation guidelines for your model.
- Spare tire and kit: may include its own size and inflation details, which are important if you need a temporary replacement.
- Manufacturer or retailer websites: input your vehicle’s year, make, and model to confirm OEM tire specs and approved alternatives.
Using these sources ensures you know the exact size, load rating, and inflation targets for safe operation and optimal performance.
Understanding the tire size code and markings
What the main size code tells you
The core size code encodes width, aspect ratio, construction, and wheel diameter. For example, in 205/55R16:
- Width: 205 millimeters (the distance from sidewall to sidewall).
- Aspect ratio: 55% (the height of the sidewall as a percentage of the width).
- Construction: R indicates radial construction.
- Rim diameter: 16 inches (the wheel size the tire fits).
- Prefix letters: P indicates a standard passenger car tire; LT indicates a light-truck tire; ST indicates a special trailer.
Concluding note: this main size code helps you confirm fit with your wheels and ensures you don’t install a tire that won’t clear suspension components or the fenders.
Additional markings and safety information
Beyond the main size code, tires carry other markings that inform load, speed, and safety features. Key elements include:
- Load index and speed rating: a number and a letter (for example, 93V) that indicate how much weight the tire can carry and the maximum safe speed.
- UTQG ratings: treadwear, traction, and temperature grades (e.g., 400 A A). These are standardized tests and may not be displayed on all tires.
- Winter/snow markings: M+S (Mud and Snow) and the Three Peak Mountain Snowflake symbol (3PMSF) indicate winter suitability.
- DOT code and manufacture date: the DOT mark followed by alphanumeric characters; the last four digits typically indicate the week and year of manufacture (e.g., 2319 = week 23 of 2019).
- Maximum load and maximum inflation pressure: printed on the sidewall; these indicate the highest load the tire can carry and the highest air pressure the tire is designed to hold.
These markings help you compare tires beyond size, including capacity, safety ratings, and age, which are important for performance and safety.
What to do with your tire specs
Follow these guidelines to ensure replacements and rotations stay aligned with your vehicle’s design and safety standards.
- Match OEM size and spec: whenever possible, replace tires with the same size, load index, and speed rating as recommended by the vehicle manufacturer.
- Avoid mixing incompatible sizes on the same axle: different sizes can affect handling and traction; if you must mix, consult the manufacturer or a tire professional.
- Follow the door placard for inflation: inflate tires to the recommended cold pressures; check pressure when tires are cold and adjust as needed.
- Check tire age and condition: tires wear out beyond tread depth and rubber degrades with time; most manufacturers recommend considering replacement around 6–10 years from the date of manufacture, regardless of tread left.
- Consider season and performance needs: all-season, summer, and winter tires have different performance characteristics; choose tires appropriate for your climate and driving habits, while sticking to compatible sizes.
By adhering to these practices, you maintain safety, optimize fuel efficiency, and preserve handling characteristics relevant to your vehicle.
Summary
Your tire specifications center on size, load index, speed rating, construction, and inflation guidance, all of which are encoded on the tire sidewall and summarized on the door placard. Reading these details—along with UTQG ratings, date of manufacture, and seasonal markings—helps you select the right tires and maintain safe performance. If you share your vehicle year, make, model, and the exact tire codes you see, I can help interpret them and confirm suitable replacement options.
