225/45R18 vs 295/35R18

295/35R18 is 0.16 in (4.0 mm) taller than 225/45R18, a +0.61% diameter difference. With the speedometer set for 225/45R18, an indicated 60 mph is 60.4 mph on 295/35R18.

Is this a safe swap?

Diameter difference +0.61%: under 1%

By overall diameter alone, 295/35R18 is a near match for 225/45R18; 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.

225/45R18 vs 295/35R18 differences
Measurement	225/45R18	295/35R18	Difference	% diff
Overall diameter	25.97 in (659.7 mm)	26.13 in (663.7 mm)	+0.16 in (+4.0 mm)	+0.61%
Sidewall height	3.99 in (101.3 mm)	4.06 in (103.3 mm)	+0.08 in (+2.0 mm)	+1.98%
Section width	8.86 in (225.0 mm)	11.61 in (295.0 mm)	+2.76 in (+70.0 mm)	+31.11%
Circumference	81.59 in (2,072.5 mm)	82.09 in (2,085.1 mm)	+0.49 in (+12.6 mm)	+0.61%
Revolutions per mile	777	772	−5	−0.60%

True speed with the speedometer calibrated for 225/45R18
Indicated	Actual on 225/45R18	Actual on 295/35R18	Difference
30 mph	30.0 mph	30.2 mph	+0.2 mph
60 mph	60.0 mph	60.4 mph	+0.4 mph
75 mph	75.0 mph	75.5 mph	+0.5 mph

Ride-height change: 295/35R18 raises the vehicle by 0.08 in (2.0 mm) at the axle (half the +4.0 mm diameter difference).

295/35R18 is 0.16 in taller than 225/45R18 and 70 mm wider, a 0.61% difference in overall diameter.

With the speedometer calibrated for 225/45R18, an indicated 60 mph is actually 60.4 mph on 295/35R18, and revolutions per mile change from 777 to 772.

Both sizes mount on 18-inch wheels.

Size pages

Other comparisons with 225/45R18

Other comparisons with 295/35R18

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