295/35R20 vs 235/45R20

235/45R20 is 0.20 in (5.0 mm) taller than 295/35R20, a +0.70% diameter difference. With the speedometer set for 295/35R20, an indicated 60 mph is 60.4 mph on 235/45R20.

Is this a safe swap?

Diameter difference +0.70%: under 1%

By overall diameter alone, 235/45R20 is a near match for 295/35R20; 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.

295/35R20 vs 235/45R20 differences
Measurement	295/35R20	235/45R20	Difference	% diff
Overall diameter	28.13 in (714.5 mm)	28.33 in (719.5 mm)	+0.20 in (+5.0 mm)	+0.70%
Sidewall height	4.06 in (103.3 mm)	4.16 in (105.8 mm)	+0.10 in (+2.5 mm)	+2.42%
Section width	11.61 in (295.0 mm)	9.25 in (235.0 mm)	−2.36 in (−60.0 mm)	−20.34%
Circumference	88.37 in (2,244.7 mm)	88.99 in (2,260.4 mm)	+0.62 in (+15.7 mm)	+0.70%
Revolutions per mile	717	712	−5	−0.69%

True speed with the speedometer calibrated for 295/35R20
Indicated	Actual on 295/35R20	Actual on 235/45R20	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: 235/45R20 raises the vehicle by 0.10 in (2.5 mm) at the axle (half the +5.0 mm diameter difference).

235/45R20 is 0.20 in taller than 295/35R20 and 60 mm narrower, a 0.70% difference in overall diameter.

With the speedometer calibrated for 295/35R20, an indicated 60 mph is actually 60.4 mph on 235/45R20, and revolutions per mile change from 717 to 712.

Both sizes mount on 20-inch wheels.

Size pages

Other comparisons with 295/35R20

Other comparisons with 235/45R20

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