TireSizesFinder

265/45R21 vs 285/45R21

285/45R21 is 0.71 in (18.0 mm) taller than 265/45R21, a +2.33% diameter difference. With the speedometer set for 265/45R21, an indicated 60 mph is 61.4 mph on 285/45R21.

Is this a safe swap?

Diameter difference +2.33%: within the ±3% guideline

By overall diameter alone, 285/45R21 falls inside the ±3% range commonly used as a guideline when replacing 265/45R21. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 265/45R21 (30.39 in) vs 285/45R21 (31.10 in)265/45R2130.39 in × 10.43 in285/45R2131.10 in × 11.22 in
Side profile and tread width, drawn to the same scale.
265/45R21 vs 285/45R21 differences
Measurement265/45R21285/45R21Difference% diff
Overall diameter30.39 in (771.9 mm)31.10 in (789.9 mm)+0.71 in (+18.0 mm)+2.33%
Sidewall height4.69 in (119.3 mm)5.05 in (128.3 mm)+0.35 in (+9.0 mm)+7.55%
Section width10.43 in (265.0 mm)11.22 in (285.0 mm)+0.79 in (+20.0 mm)+7.55%
Circumference95.47 in (2,425.0 mm)97.70 in (2,481.5 mm)+2.23 in (+56.5 mm)+2.33%
Revolutions per mile664649−15−2.28%
True speed with the speedometer calibrated for 265/45R21
IndicatedActual on 265/45R21Actual on 285/45R21Difference
30 mph30.0 mph30.7 mph+0.7 mph
60 mph60.0 mph61.4 mph+1.4 mph
75 mph75.0 mph76.7 mph+1.7 mph

Ride-height change: 285/45R21 raises the vehicle by 0.35 in (9.0 mm) at the axle (half the +18.0 mm diameter difference).

285/45R21 is 0.71 in taller than 265/45R21 and 20 mm wider, a 2.33% difference in overall diameter.

With the speedometer calibrated for 265/45R21, an indicated 60 mph is actually 61.4 mph on 285/45R21, and revolutions per mile change from 664 to 649.

Both sizes mount on 21-inch wheels.

Size pages

Other comparisons with 265/45R21

Other comparisons with 285/45R21

Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.