265/60R18 vs 275/60R18

275/60R18 is 0.47 in (12.0 mm) taller than 265/60R18, a +1.55% diameter difference. With the speedometer set for 265/60R18, an indicated 60 mph is 60.9 mph on 275/60R18.

Is this a safe swap?

Diameter difference +1.55%: within the ±3% guideline

By overall diameter alone, 275/60R18 falls inside the ±3% range commonly used as a guideline when replacing 265/60R18. 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.

265/60R18 vs 275/60R18 differences
Measurement	265/60R18	275/60R18	Difference	% diff
Overall diameter	30.52 in (775.2 mm)	30.99 in (787.2 mm)	+0.47 in (+12.0 mm)	+1.55%
Sidewall height	6.26 in (159.0 mm)	6.50 in (165.0 mm)	+0.24 in (+6.0 mm)	+3.77%
Section width	10.43 in (265.0 mm)	10.83 in (275.0 mm)	+0.39 in (+10.0 mm)	+3.77%
Circumference	95.88 in (2,435.4 mm)	97.36 in (2,473.1 mm)	+1.48 in (+37.7 mm)	+1.55%
Revolutions per mile	661	651	−10	−1.52%

True speed with the speedometer calibrated for 265/60R18
Indicated	Actual on 265/60R18	Actual on 275/60R18	Difference
30 mph	30.0 mph	30.5 mph	+0.5 mph
60 mph	60.0 mph	60.9 mph	+0.9 mph
75 mph	75.0 mph	76.2 mph	+1.2 mph

Ride-height change: 275/60R18 raises the vehicle by 0.24 in (6.0 mm) at the axle (half the +12.0 mm diameter difference).

275/60R18 is 0.47 in taller than 265/60R18 and 10 mm wider, a 1.55% difference in overall diameter.

With the speedometer calibrated for 265/60R18, an indicated 60 mph is actually 60.9 mph on 275/60R18, and revolutions per mile change from 661 to 651.

Both sizes mount on 18-inch wheels.

Size pages

Other comparisons with 265/60R18

Other comparisons with 275/60R18

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