TireSizesFinder

315/35R21 vs 285/35R22

285/35R22 is 0.17 in (4.4 mm) taller than 315/35R21, a +0.58% diameter difference. With the speedometer set for 315/35R21, an indicated 60 mph is 60.4 mph on 285/35R22.

Is this a safe swap?

Diameter difference +0.58%: under 1%

By overall diameter alone, 285/35R22 is a near match for 315/35R21; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 315/35R21 (29.68 in) vs 285/35R22 (29.85 in)315/35R2129.68 in × 12.40 in285/35R2229.85 in × 11.22 in
Side profile and tread width, drawn to the same scale.
315/35R21 vs 285/35R22 differences
Measurement315/35R21285/35R22Difference% diff
Overall diameter29.68 in (753.9 mm)29.85 in (758.3 mm)+0.17 in (+4.4 mm)+0.58%
Sidewall height4.34 in (110.3 mm)3.93 in (99.8 mm)−0.41 in (−10.5 mm)−9.52%
Section width12.40 in (315.0 mm)11.22 in (285.0 mm)−1.18 in (−30.0 mm)−9.52%
Circumference93.25 in (2,368.4 mm)93.79 in (2,382.3 mm)+0.54 in (+13.8 mm)+0.58%
Revolutions per mile679676−4−0.58%
True speed with the speedometer calibrated for 315/35R21
IndicatedActual on 315/35R21Actual on 285/35R22Difference
30 mph30.0 mph30.2 mph+0.2 mph
60 mph60.0 mph60.4 mph+0.4 mph
75 mph75.0 mph75.4 mph+0.4 mph

Ride-height change: 285/35R22 raises the vehicle by 0.09 in (2.2 mm) at the axle (half the +4.4 mm diameter difference).

285/35R22 is 0.17 in taller than 315/35R21 and 30 mm narrower, a 0.58% difference in overall diameter.

With the speedometer calibrated for 315/35R21, an indicated 60 mph is actually 60.4 mph on 285/35R22, and revolutions per mile change from 679 to 676.

285/35R22 mounts on a 22-inch wheel, a plus-1 fitment from the 21-inch wheel of 315/35R21.

Size pages

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Other comparisons with 285/35R22

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