215/55R17 vs 295/35R18

295/35R18 is 0.18 in (4.6 mm) shorter than 215/55R17, a −0.69% diameter difference. With the speedometer set for 215/55R17, an indicated 60 mph is 59.6 mph on 295/35R18.

Is this a safe swap?

Diameter difference −0.69%: under 1%

By overall diameter alone, 295/35R18 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 295/35R18 differences
Measurement	215/55R17	295/35R18	Difference	% diff
Overall diameter	26.31 in (668.3 mm)	26.13 in (663.7 mm)	−0.18 in (−4.6 mm)	−0.69%
Sidewall height	4.66 in (118.3 mm)	4.06 in (103.3 mm)	−0.59 in (−15.0 mm)	−12.68%
Section width	8.46 in (215.0 mm)	11.61 in (295.0 mm)	+3.15 in (+80.0 mm)	+37.21%
Circumference	82.66 in (2,099.5 mm)	82.09 in (2,085.1 mm)	−0.57 in (−14.5 mm)	−0.69%
Revolutions per mile	767	772	+5	+0.69%

True speed with the speedometer calibrated for 215/55R17
Indicated	Actual on 215/55R17	Actual on 295/35R18	Difference
30 mph	30.0 mph	29.8 mph	−0.2 mph
60 mph	60.0 mph	59.6 mph	−0.4 mph
75 mph	75.0 mph	74.5 mph	−0.5 mph

Ride-height change: 295/35R18 lowers the vehicle by 0.09 in (2.3 mm) at the axle (half the −4.6 mm diameter difference).

295/35R18 is 0.18 in shorter than 215/55R17 and 80 mm wider, a 0.69% difference in overall diameter.

With the speedometer calibrated for 215/55R17, an indicated 60 mph is actually 59.6 mph on 295/35R18, and revolutions per mile change from 767 to 772.

295/35R18 mounts on a 18-inch wheel, a plus-1 fitment from the 17-inch wheel of 215/55R17.

Size pages

Other comparisons with 215/55R17

Other comparisons with 295/35R18

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