245/70R16 vs 255/70R16

255/70R16 is 0.55 in (14.0 mm) taller than 245/70R16, a +1.87% diameter difference. With the speedometer set for 245/70R16, an indicated 60 mph is 61.1 mph on 255/70R16.

Is this a safe swap?

Diameter difference +1.87%: within the ±3% guideline

By overall diameter alone, 255/70R16 falls inside the ±3% range commonly used as a guideline when replacing 245/70R16. 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.

245/70R16 vs 255/70R16 differences
Measurement	245/70R16	255/70R16	Difference	% diff
Overall diameter	29.50 in (749.4 mm)	30.06 in (763.4 mm)	+0.55 in (+14.0 mm)	+1.87%
Sidewall height	6.75 in (171.5 mm)	7.03 in (178.5 mm)	+0.28 in (+7.0 mm)	+4.08%
Section width	9.65 in (245.0 mm)	10.04 in (255.0 mm)	+0.39 in (+10.0 mm)	+4.08%
Circumference	92.69 in (2,354.3 mm)	94.42 in (2,398.3 mm)	+1.73 in (+44.0 mm)	+1.87%
Revolutions per mile	684	671	−13	−1.83%

True speed with the speedometer calibrated for 245/70R16
Indicated	Actual on 245/70R16	Actual on 255/70R16	Difference
30 mph	30.0 mph	30.6 mph	+0.6 mph
60 mph	60.0 mph	61.1 mph	+1.1 mph
75 mph	75.0 mph	76.4 mph	+1.4 mph

Ride-height change: 255/70R16 raises the vehicle by 0.28 in (7.0 mm) at the axle (half the +14.0 mm diameter difference).

255/70R16 is 0.55 in taller than 245/70R16 and 10 mm wider, a 1.87% difference in overall diameter.

With the speedometer calibrated for 245/70R16, an indicated 60 mph is actually 61.1 mph on 255/70R16, and revolutions per mile change from 684 to 671.

Both sizes mount on 16-inch wheels.

Size pages

Other comparisons with 245/70R16

Other comparisons with 255/70R16

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