235/75R17 vs 235/80R17

235/80R17 is 0.93 in (23.5 mm) taller than 235/75R17, a +3.00% diameter difference. With the speedometer set for 235/75R17, an indicated 60 mph is 61.8 mph on 235/80R17.

Is this a safe swap?

Diameter difference +3.00%: within the ±3% guideline

By overall diameter alone, 235/80R17 falls inside the ±3% range commonly used as a guideline when replacing 235/75R17. 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.

235/75R17 vs 235/80R17 differences
Measurement	235/75R17	235/80R17	Difference	% diff
Overall diameter	30.88 in (784.3 mm)	31.80 in (807.8 mm)	+0.93 in (+23.5 mm)	+3.00%
Sidewall height	6.94 in (176.3 mm)	7.40 in (188.0 mm)	+0.46 in (+11.8 mm)	+6.67%
Section width	9.25 in (235.0 mm)	9.25 in (235.0 mm)	0.00 in (0.0 mm)	0.00%
Circumference	97.01 in (2,464.0 mm)	99.91 in (2,537.8 mm)	+2.91 in (+73.8 mm)	+3.00%
Revolutions per mile	653	634	−19	−2.91%

True speed with the speedometer calibrated for 235/75R17
Indicated	Actual on 235/75R17	Actual on 235/80R17	Difference
30 mph	30.0 mph	30.9 mph	+0.9 mph
60 mph	60.0 mph	61.8 mph	+1.8 mph
75 mph	75.0 mph	77.2 mph	+2.2 mph

Ride-height change: 235/80R17 raises the vehicle by 0.46 in (11.8 mm) at the axle (half the +23.5 mm diameter difference).

235/80R17 is 0.93 in taller than 235/75R17 and the same width, a 3.00% difference in overall diameter.

With the speedometer calibrated for 235/75R17, an indicated 60 mph is actually 61.8 mph on 235/80R17, and revolutions per mile change from 653 to 634.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 235/75R17

Other comparisons with 235/80R17

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