Comparison

225/35 R19 vs 225/45 R18

225/45 R18 drops the rim from 19 to 18 inches versus 225/35 R19, trading wheel size for taller sidewall. This sizing approach moves rolling diameter well outside the usual OEM tolerance. Extra sidewall absorbs impacts more readily — a sensible bias for daily commuting and broken pavement.

Indicated speed will drift far enough that recalibration is worth considering. The 3–5% diameter gap puts this in caution territory: doable on many cars, but verify clearance and consider recalibration.

TakeTypical choice for a dedicated winter or off-road setup where extra sidewall pays off.

Quick math: 225/45 R18 is 19.6 mm taller than 225/35 R19, shifting the speedometer by +3.06%.

Current Tire

225/35R19

New Tire

225/45R18
225/35 R19
225/45 R18

Ground line · scaled comparison

Slight Difference

Within ±5% — usable, recalibration recommended

Diameter change

+19.6 mm

3.06%

Speedometer at 100

103.1 km/h

+3.06% error

Ground clearance

+9.8 mm

ride height delta

Sidewall change

+22.5 mm

revs/km: 482.5

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Detailed comparison

Metric225/35 R19225/45 R18Difference
Overall diameter640.1 mm659.7 mm+19.6 mm (+3.06%)
Sidewall height78.8 mm101.3 mm+22.5 mm
Circumference2.011 m2.073 m+61.6 mm
Revs / km497.3482.5-14.8
Ground clearancereference+9.8 mm+9.8 mm
Speedometer @ 100 km/h100.0 km/h103.1 km/h+3.06 km/h

Verdict: warning

Between 3% and 5% — noticeable speedometer drift; recalibration may be advisable.

Speedometer impact

At a true 100 km/h, your dashboard will read 103.1 km/h after switching to 225/45 R18 — a +3.06% offset. Use the speedometer error calculator to recheck for other indicated speeds, and the speedometer error guide for the full background.

Ground clearance change

The new tire's half-diameter changes ride height by +9.8 mm. Small differences are absorbed by suspension travel, but anything beyond ±10 mm can affect headlight aim, fender clearance and bump-stop margin. See the plus-sizing guide before committing.

Back to

225/35 R19

Back to

225/45 R18

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Frequently asked questions