255/65R16 vs 245/70R16

245/70R16 is 0.45 in (11.5 mm) taller than 255/65R16, a +1.56% diameter difference. With the speedometer set for 255/65R16, an indicated 60 mph is 60.9 mph on 245/70R16.

Is this a safe swap?

Diameter difference +1.56%: within the ±3% guideline

By overall diameter alone, 245/70R16 falls inside the ±3% range commonly used as a guideline when replacing 255/65R16. 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.

255/65R16 vs 245/70R16 differences
Measurement	255/65R16	245/70R16	Difference	% diff
Overall diameter	29.05 in (737.9 mm)	29.50 in (749.4 mm)	+0.45 in (+11.5 mm)	+1.56%
Sidewall height	6.53 in (165.8 mm)	6.75 in (171.5 mm)	+0.23 in (+5.8 mm)	+3.47%
Section width	10.04 in (255.0 mm)	9.65 in (245.0 mm)	−0.39 in (−10.0 mm)	−3.92%
Circumference	91.27 in (2,318.2 mm)	92.69 in (2,354.3 mm)	+1.42 in (+36.1 mm)	+1.56%
Revolutions per mile	694	684	−11	−1.53%

True speed with the speedometer calibrated for 255/65R16
Indicated	Actual on 255/65R16	Actual on 245/70R16	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: 245/70R16 raises the vehicle by 0.23 in (5.8 mm) at the axle (half the +11.5 mm diameter difference).

245/70R16 is 0.45 in taller than 255/65R16 and 10 mm narrower, a 1.56% difference in overall diameter.

With the speedometer calibrated for 255/65R16, an indicated 60 mph is actually 60.9 mph on 245/70R16, and revolutions per mile change from 694 to 684.

Both sizes mount on 16-inch wheels.

Size pages

Other comparisons with 255/65R16

Other comparisons with 245/70R16

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