225/45R17 vs 245/45R17

245/45R17 is 0.71 in (18.0 mm) taller than 225/45R17, a +2.84% diameter difference. With the speedometer set for 225/45R17, an indicated 60 mph is 61.7 mph on 245/45R17.

Is this a safe swap?

Diameter difference +2.84%: within the ±3% guideline

By overall diameter alone, 245/45R17 falls inside the ±3% range commonly used as a guideline when replacing 225/45R17. 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.

225/45R17 vs 245/45R17 differences
Measurement	225/45R17	245/45R17	Difference	% diff
Overall diameter	24.97 in (634.3 mm)	25.68 in (652.3 mm)	+0.71 in (+18.0 mm)	+2.84%
Sidewall height	3.99 in (101.3 mm)	4.34 in (110.3 mm)	+0.35 in (+9.0 mm)	+8.89%
Section width	8.86 in (225.0 mm)	9.65 in (245.0 mm)	+0.79 in (+20.0 mm)	+8.89%
Circumference	78.45 in (1,992.7 mm)	80.68 in (2,049.3 mm)	+2.23 in (+56.5 mm)	+2.84%
Revolutions per mile	808	785	−22	−2.76%

True speed with the speedometer calibrated for 225/45R17
Indicated	Actual on 225/45R17	Actual on 245/45R17	Difference
30 mph	30.0 mph	30.9 mph	+0.9 mph
60 mph	60.0 mph	61.7 mph	+1.7 mph
75 mph	75.0 mph	77.1 mph	+2.1 mph

Ride-height change: 245/45R17 raises the vehicle by 0.35 in (9.0 mm) at the axle (half the +18.0 mm diameter difference).

245/45R17 is 0.71 in taller than 225/45R17 and 20 mm wider, a 2.84% difference in overall diameter.

With the speedometer calibrated for 225/45R17, an indicated 60 mph is actually 61.7 mph on 245/45R17, and revolutions per mile change from 808 to 785.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 225/45R17

Other comparisons with 245/45R17

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