215/50R17 vs 245/45R17

245/45R17 is 0.22 in (5.5 mm) taller than 215/50R17, a +0.85% diameter difference. With the speedometer set for 215/50R17, an indicated 60 mph is 60.5 mph on 245/45R17.

Is this a safe swap?

Diameter difference +0.85%: under 1%

By overall diameter alone, 245/45R17 is a near match for 215/50R17; 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.

215/50R17 vs 245/45R17 differences
Measurement	215/50R17	245/45R17	Difference	% diff
Overall diameter	25.46 in (646.8 mm)	25.68 in (652.3 mm)	+0.22 in (+5.5 mm)	+0.85%
Sidewall height	4.23 in (107.5 mm)	4.34 in (110.3 mm)	+0.11 in (+2.8 mm)	+2.56%
Section width	8.46 in (215.0 mm)	9.65 in (245.0 mm)	+1.18 in (+30.0 mm)	+13.95%
Circumference	80.00 in (2,032.0 mm)	80.68 in (2,049.3 mm)	+0.68 in (+17.3 mm)	+0.85%
Revolutions per mile	792	785	−7	−0.84%

True speed with the speedometer calibrated for 215/50R17
Indicated	Actual on 215/50R17	Actual on 245/45R17	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.5 mph	+0.5 mph
75 mph	75.0 mph	75.6 mph	+0.6 mph

Ride-height change: 245/45R17 raises the vehicle by 0.11 in (2.8 mm) at the axle (half the +5.5 mm diameter difference).

245/45R17 is 0.22 in taller than 215/50R17 and 30 mm wider, a 0.85% difference in overall diameter.

With the speedometer calibrated for 215/50R17, an indicated 60 mph is actually 60.5 mph on 245/45R17, and revolutions per mile change from 792 to 785.

Both sizes mount on 17-inch wheels.

Size pages

Other comparisons with 215/50R17

Other comparisons with 245/45R17

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