275/65R17 vs 235/80R17

235/80R17 is 0.73 in (18.5 mm) taller than 275/65R17, a +2.34% diameter difference. With the speedometer set for 275/65R17, an indicated 60 mph is 61.4 mph on 235/80R17.

Is this a safe swap?

Diameter difference +2.34%: within the ±3% guideline

By overall diameter alone, 235/80R17 falls inside the ±3% range commonly used as a guideline when replacing 275/65R17. 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.

275/65R17 vs 235/80R17 differences
Measurement	275/65R17	235/80R17	Difference	% diff
Overall diameter	31.07 in (789.3 mm)	31.80 in (807.8 mm)	+0.73 in (+18.5 mm)	+2.34%
Sidewall height	7.04 in (178.8 mm)	7.40 in (188.0 mm)	+0.36 in (+9.3 mm)	+5.17%
Section width	10.83 in (275.0 mm)	9.25 in (235.0 mm)	−1.57 in (−40.0 mm)	−14.55%
Circumference	97.62 in (2,479.7 mm)	99.91 in (2,537.8 mm)	+2.29 in (+58.1 mm)	+2.34%
Revolutions per mile	649	634	−15	−2.29%

True speed with the speedometer calibrated for 275/65R17
Indicated	Actual on 275/65R17	Actual on 235/80R17	Difference
30 mph	30.0 mph	30.7 mph	+0.7 mph
60 mph	60.0 mph	61.4 mph	+1.4 mph
75 mph	75.0 mph	76.8 mph	+1.8 mph

Ride-height change: 235/80R17 raises the vehicle by 0.36 in (9.3 mm) at the axle (half the +18.5 mm diameter difference).

235/80R17 is 0.73 in taller than 275/65R17 and 40 mm narrower, a 2.34% difference in overall diameter.

With the speedometer calibrated for 275/65R17, an indicated 60 mph is actually 61.4 mph on 235/80R17, and revolutions per mile change from 649 to 634.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 275/65R17

Other comparisons with 235/80R17

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