215/55R17 vs 305/30R19

305/30R19 is 0.11 in (2.7 mm) shorter than 215/55R17, a −0.40% diameter difference. With the speedometer set for 215/55R17, an indicated 60 mph is 59.8 mph on 305/30R19.

Is this a safe swap?

Diameter difference −0.40%: under 1%

By overall diameter alone, 305/30R19 is a near match for 215/55R17; 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.

215/55R17 vs 305/30R19 differences
Measurement	215/55R17	305/30R19	Difference	% diff
Overall diameter	26.31 in (668.3 mm)	26.20 in (665.6 mm)	−0.11 in (−2.7 mm)	−0.40%
Sidewall height	4.66 in (118.3 mm)	3.60 in (91.5 mm)	−1.05 in (−26.7 mm)	−22.62%
Section width	8.46 in (215.0 mm)	12.01 in (305.0 mm)	+3.54 in (+90.0 mm)	+41.86%
Circumference	82.66 in (2,099.5 mm)	82.32 in (2,091.0 mm)	−0.33 in (−8.5 mm)	−0.40%
Revolutions per mile	767	770	+3	+0.41%

True speed with the speedometer calibrated for 215/55R17
Indicated	Actual on 215/55R17	Actual on 305/30R19	Difference
30 mph	30.0 mph	29.9 mph	−0.1 mph
60 mph	60.0 mph	59.8 mph	−0.2 mph
75 mph	75.0 mph	74.7 mph	−0.3 mph

Ride-height change: 305/30R19 lowers the vehicle by 0.05 in (1.4 mm) at the axle (half the −2.7 mm diameter difference).

305/30R19 is 0.11 in shorter than 215/55R17 and 90 mm wider, a 0.40% difference in overall diameter.

With the speedometer calibrated for 215/55R17, an indicated 60 mph is actually 59.8 mph on 305/30R19, and revolutions per mile change from 767 to 770.

305/30R19 mounts on a 19-inch wheel, a plus-2 fitment from the 17-inch wheel of 215/55R17.

Size pages

Other comparisons with 215/55R17

Other comparisons with 305/30R19

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