245/65R17 vs 235/70R17

235/70R17 is 0.41 in (10.5 mm) taller than 245/65R17, a +1.40% diameter difference. With the speedometer set for 245/65R17, an indicated 60 mph is 60.8 mph on 235/70R17.

Is this a safe swap?

Diameter difference +1.40%: within the ±3% guideline

By overall diameter alone, 235/70R17 falls inside the ±3% range commonly used as a guideline when replacing 245/65R17. 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.

245/65R17 vs 235/70R17 differences
Measurement	245/65R17	235/70R17	Difference	% diff
Overall diameter	29.54 in (750.3 mm)	29.95 in (760.8 mm)	+0.41 in (+10.5 mm)	+1.40%
Sidewall height	6.27 in (159.3 mm)	6.48 in (164.5 mm)	+0.21 in (+5.3 mm)	+3.30%
Section width	9.65 in (245.0 mm)	9.25 in (235.0 mm)	−0.39 in (−10.0 mm)	−4.08%
Circumference	92.80 in (2,357.1 mm)	94.10 in (2,390.1 mm)	+1.30 in (+33.0 mm)	+1.40%
Revolutions per mile	683	673	−9	−1.38%

True speed with the speedometer calibrated for 245/65R17
Indicated	Actual on 245/65R17	Actual on 235/70R17	Difference
30 mph	30.0 mph	30.4 mph	+0.4 mph
60 mph	60.0 mph	60.8 mph	+0.8 mph
75 mph	75.0 mph	76.0 mph	+1.0 mph

Ride-height change: 235/70R17 raises the vehicle by 0.21 in (5.3 mm) at the axle (half the +10.5 mm diameter difference).

235/70R17 is 0.41 in taller than 245/65R17 and 10 mm narrower, a 1.40% difference in overall diameter.

With the speedometer calibrated for 245/65R17, an indicated 60 mph is actually 60.8 mph on 235/70R17, and revolutions per mile change from 683 to 673.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 245/65R17

Other comparisons with 235/70R17

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