TireSizesFinder

295/40R21 vs 255/40R22

255/40R22 is 0.26 in (6.6 mm) shorter than 295/40R21, a −0.86% diameter difference. With the speedometer set for 295/40R21, an indicated 60 mph is 59.5 mph on 255/40R22.

Is this a safe swap?

Diameter difference −0.86%: under 1%

By overall diameter alone, 255/40R22 is a near match for 295/40R21; 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: 295/40R21 (30.29 in) vs 255/40R22 (30.03 in)295/40R2130.29 in × 11.61 in255/40R2230.03 in × 10.04 in
Side profile and tread width, drawn to the same scale.
295/40R21 vs 255/40R22 differences
Measurement295/40R21255/40R22Difference% diff
Overall diameter30.29 in (769.4 mm)30.03 in (762.8 mm)−0.26 in (−6.6 mm)−0.86%
Sidewall height4.65 in (118.0 mm)4.02 in (102.0 mm)−0.63 in (−16.0 mm)−13.56%
Section width11.61 in (295.0 mm)10.04 in (255.0 mm)−1.57 in (−40.0 mm)−13.56%
Circumference95.16 in (2,417.1 mm)94.35 in (2,396.4 mm)−0.82 in (−20.7 mm)−0.86%
Revolutions per mile666672+6+0.87%
True speed with the speedometer calibrated for 295/40R21
IndicatedActual on 295/40R21Actual on 255/40R22Difference
30 mph30.0 mph29.7 mph−0.3 mph
60 mph60.0 mph59.5 mph−0.5 mph
75 mph75.0 mph74.4 mph−0.6 mph

Ride-height change: 255/40R22 lowers the vehicle by 0.13 in (3.3 mm) at the axle (half the −6.6 mm diameter difference).

255/40R22 is 0.26 in shorter than 295/40R21 and 40 mm narrower, a 0.86% difference in overall diameter.

With the speedometer calibrated for 295/40R21, an indicated 60 mph is actually 59.5 mph on 255/40R22, and revolutions per mile change from 666 to 672.

255/40R22 mounts on a 22-inch wheel, a plus-1 fitment from the 21-inch wheel of 295/40R21.

Size pages

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