265/70R15 vs 255/65R17

255/65R17 is 0.44 in (11.3 mm) taller than 265/70R15, a +1.50% diameter difference. With the speedometer set for 265/70R15, an indicated 60 mph is 60.9 mph on 255/65R17.

Is this a safe swap?

Diameter difference +1.50%: within the ±3% guideline

By overall diameter alone, 255/65R17 falls inside the ±3% range commonly used as a guideline when replacing 265/70R15. 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.

265/70R15 vs 255/65R17 differences
Measurement	265/70R15	255/65R17	Difference	% diff
Overall diameter	29.61 in (752.0 mm)	30.05 in (763.3 mm)	+0.44 in (+11.3 mm)	+1.50%
Sidewall height	7.30 in (185.5 mm)	6.53 in (165.8 mm)	−0.78 in (−19.7 mm)	−10.65%
Section width	10.43 in (265.0 mm)	10.04 in (255.0 mm)	−0.39 in (−10.0 mm)	−3.77%
Circumference	93.01 in (2,362.5 mm)	94.41 in (2,398.0 mm)	+1.40 in (+35.5 mm)	+1.50%
Revolutions per mile	681	671	−10	−1.48%

True speed with the speedometer calibrated for 265/70R15
Indicated	Actual on 265/70R15	Actual on 255/65R17	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	76.1 mph	+1.1 mph

Ride-height change: 255/65R17 raises the vehicle by 0.22 in (5.6 mm) at the axle (half the +11.3 mm diameter difference).

255/65R17 is 0.44 in taller than 265/70R15 and 10 mm narrower, a 1.50% difference in overall diameter.

With the speedometer calibrated for 265/70R15, an indicated 60 mph is actually 60.9 mph on 255/65R17, and revolutions per mile change from 681 to 671.

255/65R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 265/70R15.

Size pages

Other comparisons with 265/70R15

Other comparisons with 255/65R17

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