225/75R17 vs 245/70R17

245/70R17 is 0.22 in (5.5 mm) taller than 225/75R17, a +0.71% diameter difference. With the speedometer set for 225/75R17, an indicated 60 mph is 60.4 mph on 245/70R17.

Is this a safe swap?

Diameter difference +0.71%: under 1%

By overall diameter alone, 245/70R17 is a near match for 225/75R17; the speedometer changes by less than 1%. 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.

225/75R17 vs 245/70R17 differences
Measurement	225/75R17	245/70R17	Difference	% diff
Overall diameter	30.29 in (769.3 mm)	30.50 in (774.8 mm)	+0.22 in (+5.5 mm)	+0.71%
Sidewall height	6.64 in (168.8 mm)	6.75 in (171.5 mm)	+0.11 in (+2.8 mm)	+1.63%
Section width	8.86 in (225.0 mm)	9.65 in (245.0 mm)	+0.79 in (+20.0 mm)	+8.89%
Circumference	95.15 in (2,416.8 mm)	95.83 in (2,434.1 mm)	+0.68 in (+17.3 mm)	+0.71%
Revolutions per mile	666	661	−5	−0.71%

True speed with the speedometer calibrated for 225/75R17
Indicated	Actual on 225/75R17	Actual on 245/70R17	Difference
30 mph	30.0 mph	30.2 mph	+0.2 mph
60 mph	60.0 mph	60.4 mph	+0.4 mph
75 mph	75.0 mph	75.5 mph	+0.5 mph

Ride-height change: 245/70R17 raises the vehicle by 0.11 in (2.8 mm) at the axle (half the +5.5 mm diameter difference).

245/70R17 is 0.22 in taller than 225/75R17 and 20 mm wider, a 0.71% difference in overall diameter.

With the speedometer calibrated for 225/75R17, an indicated 60 mph is actually 60.4 mph on 245/70R17, and revolutions per mile change from 666 to 661.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 225/75R17

Other comparisons with 245/70R17

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