255/50R20 vs 265/40R22

265/40R22 is 0.31 in (7.8 mm) taller than 255/50R20, a +1.02% diameter difference. With the speedometer set for 255/50R20, an indicated 60 mph is 60.6 mph on 265/40R22.

Is this a safe swap?

Diameter difference +1.02%: within the ±3% guideline

By overall diameter alone, 265/40R22 falls inside the ±3% range commonly used as a guideline when replacing 255/50R20. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

255/50R20 vs 265/40R22 differences
Measurement	255/50R20	265/40R22	Difference	% diff
Overall diameter	30.04 in (763.0 mm)	30.35 in (770.8 mm)	+0.31 in (+7.8 mm)	+1.02%
Sidewall height	5.02 in (127.5 mm)	4.17 in (106.0 mm)	−0.85 in (−21.5 mm)	−16.86%
Section width	10.04 in (255.0 mm)	10.43 in (265.0 mm)	+0.39 in (+10.0 mm)	+3.92%
Circumference	94.37 in (2,397.0 mm)	95.34 in (2,421.5 mm)	+0.96 in (+24.5 mm)	+1.02%
Revolutions per mile	671	665	−7	−1.01%

True speed with the speedometer calibrated for 255/50R20
Indicated	Actual on 255/50R20	Actual on 265/40R22	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.6 mph	+0.6 mph
75 mph	75.0 mph	75.8 mph	+0.8 mph

Ride-height change: 265/40R22 raises the vehicle by 0.15 in (3.9 mm) at the axle (half the +7.8 mm diameter difference).

265/40R22 is 0.31 in taller than 255/50R20 and 10 mm wider, a 1.02% difference in overall diameter.

With the speedometer calibrated for 255/50R20, an indicated 60 mph is actually 60.6 mph on 265/40R22, and revolutions per mile change from 671 to 665.

265/40R22 mounts on a 22-inch wheel, a plus-2 fitment from the 20-inch wheel of 255/50R20.

Size pages

Other comparisons with 255/50R20

Other comparisons with 265/40R22

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.