215/65R15 vs 245/45R17

245/45R17 is 0.32 in (8.2 mm) shorter than 215/65R15, a −1.24% diameter difference. With the speedometer set for 215/65R15, an indicated 60 mph is 59.3 mph on 245/45R17.

Is this a safe swap?

Diameter difference −1.24%: within the ±3% guideline

By overall diameter alone, 245/45R17 falls inside the ±3% range commonly used as a guideline when replacing 215/65R15. 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.

215/65R15 vs 245/45R17 differences
Measurement	215/65R15	245/45R17	Difference	% diff
Overall diameter	26.00 in (660.5 mm)	25.68 in (652.3 mm)	−0.32 in (−8.2 mm)	−1.24%
Sidewall height	5.50 in (139.8 mm)	4.34 in (110.3 mm)	−1.16 in (−29.5 mm)	−21.11%
Section width	8.46 in (215.0 mm)	9.65 in (245.0 mm)	+1.18 in (+30.0 mm)	+13.95%
Circumference	81.69 in (2,075.0 mm)	80.68 in (2,049.3 mm)	−1.01 in (−25.8 mm)	−1.24%
Revolutions per mile	776	785	+10	+1.26%

True speed with the speedometer calibrated for 215/65R15
Indicated	Actual on 215/65R15	Actual on 245/45R17	Difference
30 mph	30.0 mph	29.6 mph	−0.4 mph
60 mph	60.0 mph	59.3 mph	−0.7 mph
75 mph	75.0 mph	74.1 mph	−0.9 mph

Ride-height change: 245/45R17 lowers the vehicle by 0.16 in (4.1 mm) at the axle (half the −8.2 mm diameter difference).

245/45R17 is 0.32 in shorter than 215/65R15 and 30 mm wider, a 1.24% difference in overall diameter.

With the speedometer calibrated for 215/65R15, an indicated 60 mph is actually 59.3 mph on 245/45R17, and revolutions per mile change from 776 to 785.

245/45R17 mounts on a 17-inch wheel, a plus-2 fitment from the 15-inch wheel of 215/65R15.

Size pages

Other comparisons with 215/65R15

Other comparisons with 245/45R17

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