Comparison

225/35 R19 vs 235/45 R18

Minus-sizing from 225/35 R19 to 235/45 R18 pairs a smaller 18-inch wheel with more rubber between the rim and road. This wheel and tire pairing noticeably changes overall diameter compared to OEM. The speedometer error is noticeable and may warrant a recalibration if you rely on indicated speed. The taller sidewall adds cushioning over potholes and rougher roads, with a softer overall ride. 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: 235/45 R18 is 28.6 mm taller than 225/35 R19, shifting the speedometer by +4.47%.

Current Tire

225/35R19

New Tire

235/45R18
225/35 R19
235/45 R18

Ground line · scaled comparison

Slight Difference

Within ±5% — usable, recalibration recommended

Diameter change

+28.6 mm

4.47%

Speedometer at 100

104.5 km/h

+4.47% error

Ground clearance

+14.3 mm

ride height delta

Sidewall change

+27.0 mm

revs/km: 476.0

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Detailed comparison

Metric225/35 R19235/45 R18Difference
Overall diameter640.1 mm668.7 mm+28.6 mm (+4.47%)
Sidewall height78.8 mm105.8 mm+27.0 mm
Circumference2.011 m2.101 m+89.8 mm
Revs / km497.3476.0-21.3
Ground clearancereference+14.3 mm+14.3 mm
Speedometer @ 100 km/h100.0 km/h104.5 km/h+4.47 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 104.5 km/h after switching to 235/45 R18 — a +4.47% 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 +14.3 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

235/45 R18

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Frequently asked questions