TireSizesFinder

305/35R19 vs 265/35R20

265/35R20 is 0.10 in (2.6 mm) shorter than 305/35R19, a −0.37% diameter difference. With the speedometer set for 305/35R19, an indicated 60 mph is 59.8 mph on 265/35R20.

Is this a safe swap?

Diameter difference −0.37%: under 1%

By overall diameter alone, 265/35R20 is a near match for 305/35R19; 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: 305/35R19 (27.41 in) vs 265/35R20 (27.30 in)305/35R1927.41 in × 12.01 in265/35R2027.30 in × 10.43 in
Side profile and tread width, drawn to the same scale.
305/35R19 vs 265/35R20 differences
Measurement305/35R19265/35R20Difference% diff
Overall diameter27.41 in (696.1 mm)27.30 in (693.5 mm)−0.10 in (−2.6 mm)−0.37%
Sidewall height4.20 in (106.8 mm)3.65 in (92.8 mm)−0.55 in (−14.0 mm)−13.11%
Section width12.01 in (305.0 mm)10.43 in (265.0 mm)−1.57 in (−40.0 mm)−13.11%
Circumference86.10 in (2,186.9 mm)85.78 in (2,178.7 mm)−0.32 in (−8.2 mm)−0.37%
Revolutions per mile736739+3+0.37%
True speed with the speedometer calibrated for 305/35R19
IndicatedActual on 305/35R19Actual on 265/35R20Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.8 mph−0.2 mph
75 mph75.0 mph74.7 mph−0.3 mph

Ride-height change: 265/35R20 lowers the vehicle by 0.05 in (1.3 mm) at the axle (half the −2.6 mm diameter difference).

265/35R20 is 0.10 in shorter than 305/35R19 and 40 mm narrower, a 0.37% difference in overall diameter.

With the speedometer calibrated for 305/35R19, an indicated 60 mph is actually 59.8 mph on 265/35R20, and revolutions per mile change from 736 to 739.

265/35R20 mounts on a 20-inch wheel, a plus-1 fitment from the 19-inch wheel of 305/35R19.

Size pages

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