TireSizesFinder

295/70R18 vs 275/65R20

275/65R20 is 0.19 in (4.7 mm) shorter than 295/70R18, a −0.54% diameter difference. With the speedometer set for 295/70R18, an indicated 60 mph is 59.7 mph on 275/65R20.

Is this a safe swap?

Diameter difference −0.54%: under 1%

By overall diameter alone, 275/65R20 is a near match for 295/70R18; 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: 295/70R18 (34.26 in) vs 275/65R20 (34.07 in)295/70R1834.26 in × 11.61 in275/65R2034.07 in × 10.83 in
Side profile and tread width, drawn to the same scale.
295/70R18 vs 275/65R20 differences
Measurement295/70R18275/65R20Difference% diff
Overall diameter34.26 in (870.2 mm)34.07 in (865.5 mm)−0.19 in (−4.7 mm)−0.54%
Sidewall height8.13 in (206.5 mm)7.04 in (178.8 mm)−1.09 in (−27.7 mm)−13.44%
Section width11.61 in (295.0 mm)10.83 in (275.0 mm)−0.79 in (−20.0 mm)−6.78%
Circumference107.63 in (2,733.8 mm)107.05 in (2,719.0 mm)−0.58 in (−14.8 mm)−0.54%
Revolutions per mile589592+3+0.54%
True speed with the speedometer calibrated for 295/70R18
IndicatedActual on 295/70R18Actual on 275/65R20Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.7 mph−0.3 mph
75 mph75.0 mph74.6 mph−0.4 mph

Ride-height change: 275/65R20 lowers the vehicle by 0.09 in (2.4 mm) at the axle (half the −4.7 mm diameter difference).

275/65R20 is 0.19 in shorter than 295/70R18 and 20 mm narrower, a 0.54% difference in overall diameter.

With the speedometer calibrated for 295/70R18, an indicated 60 mph is actually 59.7 mph on 275/65R20, and revolutions per mile change from 589 to 592.

275/65R20 mounts on a 20-inch wheel, a plus-2 fitment from the 18-inch wheel of 295/70R18.

Size pages

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