TireSizesFinder

255/45R21 vs 265/40R22

265/40R22 is 0.31 in (7.9 mm) taller than 255/45R21, a +1.04% diameter difference. With the speedometer set for 255/45R21, an indicated 60 mph is 60.6 mph on 265/40R22.

Is this a safe swap?

Diameter difference +1.04%: within the ±3% guideline

By overall diameter alone, 265/40R22 falls inside the ±3% range commonly used as a guideline when replacing 255/45R21. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 255/45R21 (30.04 in) vs 265/40R22 (30.35 in)255/45R2130.04 in × 10.04 in265/40R2230.35 in × 10.43 in
Side profile and tread width, drawn to the same scale.
255/45R21 vs 265/40R22 differences
Measurement255/45R21265/40R22Difference% diff
Overall diameter30.04 in (762.9 mm)30.35 in (770.8 mm)+0.31 in (+7.9 mm)+1.04%
Sidewall height4.52 in (114.8 mm)4.17 in (106.0 mm)−0.34 in (−8.7 mm)−7.63%
Section width10.04 in (255.0 mm)10.43 in (265.0 mm)+0.39 in (+10.0 mm)+3.92%
Circumference94.36 in (2,396.7 mm)95.34 in (2,421.5 mm)+0.98 in (+24.8 mm)+1.04%
Revolutions per mile671665−7−1.02%
True speed with the speedometer calibrated for 255/45R21
IndicatedActual on 255/45R21Actual on 265/40R22Difference
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: 265/40R22 raises the vehicle by 0.16 in (3.9 mm) at the axle (half the +7.9 mm diameter difference).

265/40R22 is 0.31 in taller than 255/45R21 and 10 mm wider, a 1.04% difference in overall diameter.

With the speedometer calibrated for 255/45R21, 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-1 fitment from the 21-inch wheel of 255/45R21.

Size pages

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