265/70R17 vs 285/70R17: Tire Size Comparison
265/70R17 has an overall diameter of 31.61 in (802.8 mm). 285/70R17 has an overall diameter of 32.71 in (830.8 mm), a difference of 1.10 in (28.0 mm) (3.49%). Both sizes mount on the same 17-inch wheel diameter and share the same 70 aspect ratio; 285/70R17 is wider than 265/70R17 at that same aspect ratio (see the section-width row below for the exact difference).
| Metric | 265/70R17 | 285/70R17 | Difference |
|---|---|---|---|
| Section width | 10.43 in (265.0 mm) | 11.22 in (285.0 mm) | 0.79 in (20.0 mm) |
| Sidewall height | 7.30 in (185.5 mm) | 7.85 in (199.5 mm) | 0.55 in (14.0 mm) |
| Overall diameter | 31.61 in (802.8 mm) | 32.71 in (830.8 mm) | 1.10 in (28.0 mm) (3.49%) |
| Revolutions per mile | 638.1 | 616.6 | -21.5 |
Speedometer effect
Because 285/70R17 has a larger overall diameter, a speedometer calibrated for 265/70R17 would under-read once 285/70R17 is fitted: an indicated 60 mph corresponds to about 62.1 mph actual, using the ratio of the two diameters (32.71 in (830.8 mm) / 31.61 in (802.8 mm)). This is the sizes' geometry only, not a manufacturer-measured rolling diameter or a specific vehicle's speedometer calibration.
Sources and limits
Every figure on this page comes from the two tire sizes entered, computed by this site's geometry engine -- not from a manufacturer specification or a claim that either size is interchangeable on any particular vehicle or wheel well. Check your vehicle's owner's manual and the wheel manufacturer's fitment guidance before changing tire size. Full limits are covered on the site disclaimer page. Compare your own sizes with the tire size calculator.