235/80R17 vs 275/70R17

275/70R17 is 0.35 in (9.0 mm) taller than 235/80R17, a +1.11% diameter difference. With the speedometer set for 235/80R17, an indicated 60 mph is 60.7 mph on 275/70R17.

Is this a safe swap?

Diameter difference +1.11%: within the ±3% guideline

By overall diameter alone, 275/70R17 falls inside the ±3% range commonly used as a guideline when replacing 235/80R17. 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.

235/80R17 vs 275/70R17 differences
Measurement	235/80R17	275/70R17	Difference	% diff
Overall diameter	31.80 in (807.8 mm)	32.16 in (816.8 mm)	+0.35 in (+9.0 mm)	+1.11%
Sidewall height	7.40 in (188.0 mm)	7.58 in (192.5 mm)	+0.18 in (+4.5 mm)	+2.39%
Section width	9.25 in (235.0 mm)	10.83 in (275.0 mm)	+1.57 in (+40.0 mm)	+17.02%
Circumference	99.91 in (2,537.8 mm)	101.03 in (2,566.1 mm)	+1.11 in (+28.3 mm)	+1.11%
Revolutions per mile	634	627	−7	−1.10%

True speed with the speedometer calibrated for 235/80R17
Indicated	Actual on 235/80R17	Actual on 275/70R17	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.7 mph	+0.7 mph
75 mph	75.0 mph	75.8 mph	+0.8 mph

Ride-height change: 275/70R17 raises the vehicle by 0.18 in (4.5 mm) at the axle (half the +9.0 mm diameter difference).

275/70R17 is 0.35 in taller than 235/80R17 and 40 mm wider, a 1.11% difference in overall diameter.

With the speedometer calibrated for 235/80R17, an indicated 60 mph is actually 60.7 mph on 275/70R17, and revolutions per mile change from 634 to 627.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 235/80R17

Other comparisons with 275/70R17

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