TireSizesFinder

215/50R18 vs 225/35R20

225/35R20 is 0.26 in (6.7 mm) shorter than 215/50R18, a −1.00% diameter difference. With the speedometer set for 215/50R18, an indicated 60 mph is 59.4 mph on 225/35R20.

Is this a safe swap?

Diameter difference −1.00%: under 1%

By overall diameter alone, 225/35R20 is a near match for 215/50R18; 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: 215/50R18 (26.46 in) vs 225/35R20 (26.20 in)215/50R1826.46 in × 8.46 in225/35R2026.20 in × 8.86 in
Side profile and tread width, drawn to the same scale.
215/50R18 vs 225/35R20 differences
Measurement215/50R18225/35R20Difference% diff
Overall diameter26.46 in (672.2 mm)26.20 in (665.5 mm)−0.26 in (−6.7 mm)−1.00%
Sidewall height4.23 in (107.5 mm)3.10 in (78.8 mm)−1.13 in (−28.7 mm)−26.74%
Section width8.46 in (215.0 mm)8.86 in (225.0 mm)+0.39 in (+10.0 mm)+4.65%
Circumference83.14 in (2,111.8 mm)82.31 in (2,090.7 mm)−0.83 in (−21.0 mm)−1.00%
Revolutions per mile762770+8+1.01%
True speed with the speedometer calibrated for 215/50R18
IndicatedActual on 215/50R18Actual on 225/35R20Difference
30 mph30.0 mph29.7 mph−0.3 mph
60 mph60.0 mph59.4 mph−0.6 mph
75 mph75.0 mph74.3 mph−0.7 mph

Ride-height change: 225/35R20 lowers the vehicle by 0.13 in (3.4 mm) at the axle (half the −6.7 mm diameter difference).

225/35R20 is 0.26 in shorter than 215/50R18 and 10 mm wider, a 1.00% difference in overall diameter.

With the speedometer calibrated for 215/50R18, an indicated 60 mph is actually 59.4 mph on 225/35R20, and revolutions per mile change from 762 to 770.

225/35R20 mounts on a 20-inch wheel, a plus-2 fitment from the 18-inch wheel of 215/50R18.

Size pages

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