275/70R18 vs 295/60R20

295/60R20 is 0.78 in (19.8 mm) taller than 275/70R18, a +2.35% diameter difference. With the speedometer set for 275/70R18, an indicated 60 mph is 61.4 mph on 295/60R20.

Is this a safe swap?

Diameter difference +2.35%: within the ±3% guideline

By overall diameter alone, 295/60R20 falls inside the ±3% range commonly used as a guideline when replacing 275/70R18. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

275/70R18 vs 295/60R20 differences
Measurement	275/70R18	295/60R20	Difference	% diff
Overall diameter	33.16 in (842.2 mm)	33.94 in (862.0 mm)	+0.78 in (+19.8 mm)	+2.35%
Sidewall height	7.58 in (192.5 mm)	6.97 in (177.0 mm)	−0.61 in (−15.5 mm)	−8.05%
Section width	10.83 in (275.0 mm)	11.61 in (295.0 mm)	+0.79 in (+20.0 mm)	+7.27%
Circumference	104.17 in (2,645.8 mm)	106.62 in (2,708.1 mm)	+2.45 in (+62.2 mm)	+2.35%
Revolutions per mile	608	594	−14	−2.30%

True speed with the speedometer calibrated for 275/70R18
Indicated	Actual on 275/70R18	Actual on 295/60R20	Difference
30 mph	30.0 mph	30.7 mph	+0.7 mph
60 mph	60.0 mph	61.4 mph	+1.4 mph
75 mph	75.0 mph	76.8 mph	+1.8 mph

Ride-height change: 295/60R20 raises the vehicle by 0.39 in (9.9 mm) at the axle (half the +19.8 mm diameter difference).

295/60R20 is 0.78 in taller than 275/70R18 and 20 mm wider, a 2.35% difference in overall diameter.

With the speedometer calibrated for 275/70R18, an indicated 60 mph is actually 61.4 mph on 295/60R20, and revolutions per mile change from 608 to 594.

295/60R20 mounts on a 20-inch wheel, a plus-2 fitment from the 18-inch wheel of 275/70R18.

Size pages

Other comparisons with 275/70R18

Other comparisons with 295/60R20

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.