TireSizesFinder

275/45R20 vs 285/45R20

285/45R20 is 0.35 in (9.0 mm) taller than 275/45R20, a +1.19% diameter difference. With the speedometer set for 275/45R20, an indicated 60 mph is 60.7 mph on 285/45R20.

Is this a safe swap?

Diameter difference +1.19%: within the ±3% guideline

By overall diameter alone, 285/45R20 falls inside the ±3% range commonly used as a guideline when replacing 275/45R20. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 275/45R20 (29.74 in) vs 285/45R20 (30.10 in)275/45R2029.74 in × 10.83 in285/45R2030.10 in × 11.22 in
Side profile and tread width, drawn to the same scale.
275/45R20 vs 285/45R20 differences
Measurement275/45R20285/45R20Difference% diff
Overall diameter29.74 in (755.5 mm)30.10 in (764.5 mm)+0.35 in (+9.0 mm)+1.19%
Sidewall height4.87 in (123.8 mm)5.05 in (128.3 mm)+0.18 in (+4.5 mm)+3.64%
Section width10.83 in (275.0 mm)11.22 in (285.0 mm)+0.39 in (+10.0 mm)+3.64%
Circumference93.44 in (2,373.5 mm)94.56 in (2,401.7 mm)+1.11 in (+28.3 mm)+1.19%
Revolutions per mile678670−8−1.18%
True speed with the speedometer calibrated for 275/45R20
IndicatedActual on 275/45R20Actual on 285/45R20Difference
30 mph30.0 mph30.4 mph+0.4 mph
60 mph60.0 mph60.7 mph+0.7 mph
75 mph75.0 mph75.9 mph+0.9 mph

Ride-height change: 285/45R20 raises the vehicle by 0.18 in (4.5 mm) at the axle (half the +9.0 mm diameter difference).

285/45R20 is 0.35 in taller than 275/45R20 and 10 mm wider, a 1.19% difference in overall diameter.

With the speedometer calibrated for 275/45R20, an indicated 60 mph is actually 60.7 mph on 285/45R20, and revolutions per mile change from 678 to 670.

Both sizes mount on 20-inch wheels.

Size pages

Other comparisons with 275/45R20

Other comparisons with 285/45R20

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