255/70R17 vs 265/70R17

265/70R17 is 0.55 in (14.0 mm) taller than 255/70R17, a +1.77% diameter difference. With the speedometer set for 255/70R17, an indicated 60 mph is 61.1 mph on 265/70R17.

Is this a safe swap?

Diameter difference +1.77%: within the ±3% guideline

By overall diameter alone, 265/70R17 falls inside the ±3% range commonly used as a guideline when replacing 255/70R17. 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.

255/70R17 vs 265/70R17 differences
Measurement	255/70R17	265/70R17	Difference	% diff
Overall diameter	31.06 in (788.8 mm)	31.61 in (802.8 mm)	+0.55 in (+14.0 mm)	+1.77%
Sidewall height	7.03 in (178.5 mm)	7.30 in (185.5 mm)	+0.28 in (+7.0 mm)	+3.92%
Section width	10.04 in (255.0 mm)	10.43 in (265.0 mm)	+0.39 in (+10.0 mm)	+3.92%
Circumference	97.56 in (2,478.1 mm)	99.29 in (2,522.1 mm)	+1.73 in (+44.0 mm)	+1.77%
Revolutions per mile	649	638	−11	−1.74%

True speed with the speedometer calibrated for 255/70R17
Indicated	Actual on 255/70R17	Actual on 265/70R17	Difference
30 mph	30.0 mph	30.5 mph	+0.5 mph
60 mph	60.0 mph	61.1 mph	+1.1 mph
75 mph	75.0 mph	76.3 mph	+1.3 mph

Ride-height change: 265/70R17 raises the vehicle by 0.28 in (7.0 mm) at the axle (half the +14.0 mm diameter difference).

265/70R17 is 0.55 in taller than 255/70R17 and 10 mm wider, a 1.77% difference in overall diameter.

With the speedometer calibrated for 255/70R17, an indicated 60 mph is actually 61.1 mph on 265/70R17, and revolutions per mile change from 649 to 638.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 255/70R17

Other comparisons with 265/70R17

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