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How to Find Your Tire Size

Knowing the tire size is extremely helpful when it’s time to replace your tires. Here’s how to decipher one of the best-kept secrets in the automotive world:

find your tire size

TIRE SIZE – 225/50R17

  • 225 identifies the tire’s width which is the measurement of the tire from sidewall to sidewall in millimeters.
  • 50 is the aspect ratio. This percentage compares the tire’s section (sidewall) height with the tire’s width. For example, the aspect ratio of 50 means that the tire’s sidewall height is 50% of its width.
  • R indicates the construction used – R stands for radial construction. B means belted bias and D stands for diagonal bias construction. (Almost every tire is a radial today.)
  • 17 The last dimension listed in the size is the diameter of the wheel rim, measured in inches.


  • 98 is the load index.
  • H is the performance rating.

For the purpose of buying tires, as long as the replacement tire is equal to or greater than the tire you’re replacing, there’s nothing more you need to know about the load index and speed rating.

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