TireSizesFinder

245/40R21 vs 255/35R22

255/35R22 is 0.31 in (7.9 mm) taller than 245/40R21, a +1.08% diameter difference. With the speedometer set for 245/40R21, an indicated 60 mph is 60.6 mph on 255/35R22.

Is this a safe swap?

Diameter difference +1.08%: within the ±3% guideline

By overall diameter alone, 255/35R22 falls inside the ±3% range commonly used as a guideline when replacing 245/40R21. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 245/40R21 (28.72 in) vs 255/35R22 (29.03 in)245/40R2128.72 in × 9.65 in255/35R2229.03 in × 10.04 in
Side profile and tread width, drawn to the same scale.
245/40R21 vs 255/35R22 differences
Measurement245/40R21255/35R22Difference% diff
Overall diameter28.72 in (729.4 mm)29.03 in (737.3 mm)+0.31 in (+7.9 mm)+1.08%
Sidewall height3.86 in (98.0 mm)3.51 in (89.3 mm)−0.34 in (−8.7 mm)−8.93%
Section width9.65 in (245.0 mm)10.04 in (255.0 mm)+0.39 in (+10.0 mm)+4.08%
Circumference90.22 in (2,291.5 mm)91.19 in (2,316.3 mm)+0.98 in (+24.8 mm)+1.08%
Revolutions per mile702695−8−1.07%
True speed with the speedometer calibrated for 245/40R21
IndicatedActual on 245/40R21Actual on 255/35R22Difference
30 mph30.0 mph30.3 mph+0.3 mph
60 mph60.0 mph60.6 mph+0.6 mph
75 mph75.0 mph75.8 mph+0.8 mph

Ride-height change: 255/35R22 raises the vehicle by 0.16 in (3.9 mm) at the axle (half the +7.9 mm diameter difference).

255/35R22 is 0.31 in taller than 245/40R21 and 10 mm wider, a 1.08% difference in overall diameter.

With the speedometer calibrated for 245/40R21, an indicated 60 mph is actually 60.6 mph on 255/35R22, and revolutions per mile change from 702 to 695.

255/35R22 mounts on a 22-inch wheel, a plus-1 fitment from the 21-inch wheel of 245/40R21.

Size pages

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