Tire size field guide / Comparison index
Tire Size Comparisons
Browse common tire size changes and compare their dimensions in the calculator.
Size change, visualized
225/65R17 to 235/60R18
Outlined is the current tire; green is the new tire.
Last checked 12 October 2026Published by Sidewall GuideFormulas follow the Tire and Rim Association and ETRTO size conventions
Editorial details
Who prepared these comparisons
Written and checked by Noam Cohen, editor of Tire Size Guide Publishing. Figures were last checked 12 October 2026 against the site's published formulas. No independent technical reviewer or consumer rating is represented here; these are nominal size calculations, not road tests or vehicle fitment approvals.
The lineup
Common size pairings
01 — 12
Filter by wheel diameter
Choose a wheel size to show comparisons that include it; this is a browsing aid, not a fitment recommendation.
Showing 12 of 12 comparisons.
| Comparison | Current diameter | New diameter | Change |
|---|---|---|---|
| 01225/65R17 vs 235/60R18 | 28.52 in (724 mm) | 29.10 in (739 mm) | +2.1% |
| 02265/70R17 vs 285/70R17 | 31.61 in (803 mm) | 32.71 in (831 mm) | +3.5% |
| 03275/60R20 vs 275/65R20 | 32.99 in (838 mm) | 34.07 in (865 mm) | +3.3% |
| 04205/55R16 vs 225/45R17 | 24.88 in (632 mm) | 24.97 in (634 mm) | +0.4% |
| 05225/65R17 vs 235/65R17 | 28.52 in (724 mm) | 29.03 in (737 mm) | +1.8% |
| 06245/75R16 vs 265/75R16 | 30.47 in (774 mm) | 31.65 in (804 mm) | +3.9% |
| 07265/75R16 vs 285/75R16 | 31.65 in (804 mm) | 32.83 in (834 mm) | +3.7% |
| 08275/55R20 vs 275/60R20 | 31.91 in (811 mm) | 32.99 in (838 mm) | +3.4% |
| 09235/65R17 vs 235/60R18 | 29.03 in (737 mm) | 29.10 in (739 mm) | +0.3% |
| 10225/45R17 vs 225/40R18 | 24.97 in (634 mm) | 25.09 in (637 mm) | +0.5% |
| 11265/70R17 vs 265/65R18 | 31.61 in (803 mm) | 31.56 in (802 mm) | −0.1% |
| 12285/75R16 vs 33x12.50R15 | 32.83 in (834 mm) | 33.00 in (838 mm) | +0.5% |
How to read the change
Diameter affects speed and clearance
The percentage compares the new tire's overall diameter with the current tire. A larger diameter travels farther per rotation, so the speedometer reads low; half the diameter change also raises or lowers ride height. Width changes affect space at both tread edges.
Worked example: 225/65R17 to 235/60R18 changes from 28.52 in to 29.10 in, or +2.1%. At an indicated 60 mph, the estimated road speed is 61.2 mph, and ride height rises about 0.29 in.
These are nominal size calculations. Actual dimensions vary by tire model, and the figures do not establish vehicle fitment.
Choose your next step
Check the details that matter
- Compare your exact sizes
See diameter, speedometer, width and ride-height changes for any tire sizes.
- Browse the tire size chart
Review common sizes grouped by wheel diameter.
- Check wheel offset changes
Estimate how a different wheel moves inward or outward.
- Review the calculation method
See formulas, rounding and assumptions behind these estimates.
Before choosing a size, verify the tire maker's approved rim width and load index, then check clearance through steering and suspension travel. Similar diameter alone does not confirm fitment.