tire size comparison

Tire sizes can be compared by breaking the code on the sidewall into three main pieces and then translating those into real‑world dimensions like overall diameter, width, and sidewall height.

How tire sizes are written

For a common metric size like 225/45R17 :

• 225 = section width in millimeters (roughly how wide the tire is).
• 45 = aspect ratio (sidewall height is 45% of the width).
• R = radial construction (almost all modern tires).
• 17 = wheel diameter in inches.

There are also “flotation” sizes like 33x12.50R17 , where:

• 33 = overall diameter in inches.
• 12.50 = width in inches.
• 17 = wheel diameter in inches.

What changes when tire size changes

When you compare two sizes, you are really comparing:

• Overall diameter (affects speedometer, gearing, and fender clearance).
• Width (affects grip, fitment to the wheel and fenders, hydroplaning).
• Sidewall height (affects ride comfort, handling feel, and wheel protection).
• Circumference and revs per mile (affect indicated speed vs actual speed).

Example: going from 205/55R16 to 225/45R17 usually makes the tire a bit wider with a shorter sidewall, which firms up handling but may ride slightly harsher and be more prone to wheel damage on potholes.

Simple rules of thumb

• Keep overall diameter within about ±3% of stock so the speedometer and ABS systems stay happy.

• Make sure the new width is still approved for your wheel width (each tire size has a recommended rim-width range).

• Lower aspect ratio = stiffer feel and sharper response, but less comfort and impact protection.
• Higher aspect ratio = more comfort and sidewall flex, but less precise steering.

Example HTML table for tire size comparison

Below is an example of how you might present a tire size comparison as HTML. The numbers are typical approximations, just to show the structure (exact values vary slightly by brand):

html

<table>
  <thead>
    <tr>
      <th>Metric Size</th>
      <th>Overall Diameter (in)</th>
      <th>Tread Width (in)</th>
      <th>Sidewall Height (in)</th>
      <th>Circumference (in)</th>
      <th>Revs per Mile</th>
      <th>Notes</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>205/55R16</td>
      <td>24.9</td>
      <td>8.1</td>
      <td>4.4</td>
      <td>78.2</td>
      <td>811</td>
      <td>Common compact sedan stock size.</td>
    </tr>
    <tr>
      <td>215/55R16</td>
      <td>25.3</td>
      <td>8.5</td>
      <td>4.7</td>
      <td>79.4</td>
      <td>798</td>
      <td>Slightly taller and wider, softer ride, minor speedometer change.</td>
    </tr>
    <tr>
      <td>225/45R17</td>
      <td>25.0</td>
      <td>8.9</td>
      <td>4.0</td>
      <td>78.5</td>
      <td>807</td>
      <td>Sportier option with shorter sidewall, similar diameter to 205/55R16.</td>
    </tr>
    <tr>
      <td>235/45R17</td>
      <td>25.3</td>
      <td>9.3</td>
      <td>4.2</td>
      <td>79.4</td>
      <td>798</td>
      <td>More grip and width; check fender and steering clearance.</td>
    </tr>
  </tbody>
</table>

This format mirrors what online tire comparison tools and size charts show when they list diameter, width, sidewall, circumference, and revolutions per mile for each size.

Speedometer and “plus sizing”

If you “plus size” (for example 16 → 17 → 18 inch wheels), the usual goal is to increase wheel diameter while decreasing tire sidewall so overall diameter stays about the same.

• If the new tire is larger in diameter, your speedometer will read lower than your actual speed.
• If the new tire is smaller in diameter, your speedometer will read higher than your actual speed.

Online comparison calculators let you enter two sizes and show the speedometer error, ground clearance change, and revs‑per‑mile difference in one view.

If you tell me the two (or more) specific sizes you want to compare, I can sketch a similar HTML table tailored to those exact sizes.