TireSizesFinder

235/45R20 vs 265/35R21

265/35R21 is 0.02 in (0.6 mm) shorter than 235/45R20, a −0.08% diameter difference. With the speedometer set for 235/45R20, an indicated 60 mph is 59.9 mph on 265/35R21.

Is this a safe swap?

Diameter difference −0.08%: under 1%

By overall diameter alone, 265/35R21 is a near match for 235/45R20; 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: 235/45R20 (28.33 in) vs 265/35R21 (28.30 in)235/45R2028.33 in × 9.25 in265/35R2128.30 in × 10.43 in
Side profile and tread width, drawn to the same scale.
235/45R20 vs 265/35R21 differences
Measurement235/45R20265/35R21Difference% diff
Overall diameter28.33 in (719.5 mm)28.30 in (718.9 mm)−0.02 in (−0.6 mm)−0.08%
Sidewall height4.16 in (105.8 mm)3.65 in (92.8 mm)−0.51 in (−13.0 mm)−12.29%
Section width9.25 in (235.0 mm)10.43 in (265.0 mm)+1.18 in (+30.0 mm)+12.77%
Circumference88.99 in (2,260.4 mm)88.92 in (2,258.5 mm)−0.07 in (−1.9 mm)−0.08%
Revolutions per mile712713+1+0.08%
True speed with the speedometer calibrated for 235/45R20
IndicatedActual on 235/45R20Actual on 265/35R21Difference
30 mph30.0 mph30.0 mph0.0 mph
60 mph60.0 mph59.9 mph−0.1 mph
75 mph75.0 mph74.9 mph−0.1 mph

Ride-height change: 265/35R21 lowers the vehicle by 0.01 in (0.3 mm) at the axle (half the −0.6 mm diameter difference).

265/35R21 is 0.02 in shorter than 235/45R20 and 30 mm wider, a 0.08% difference in overall diameter.

With the speedometer calibrated for 235/45R20, an indicated 60 mph is actually 59.9 mph on 265/35R21, and revolutions per mile change from 712 to 713.

265/35R21 mounts on a 21-inch wheel, a plus-1 fitment from the 20-inch wheel of 235/45R20.

Size pages

Other comparisons with 235/45R20

Other comparisons with 265/35R21

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