Comparison
235/35 R19 vs 235/45 R18
Minus-sizing from 235/35 R19 to 235/45 R18 pairs a smaller 18-inch wheel with more rubber between the rim and road. This wheel and tire pairing moves rolling diameter well outside the usual OEM tolerance.
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 smaller wheel is also lighter and easier to find affordable winter rubber for. 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 21.6 mm taller than 235/35 R19, shifting the speedometer by +3.34%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+21.6 mm
3.34%
Speedometer at 100
103.3 km/h
+3.34% error
Ground clearance
+10.8 mm
ride height delta
Sidewall change
+23.5 mm
revs/km: 476.0
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/compare/235-35-r19-vs-235-45-r18Detailed comparison
| Metric | 235/35 R19 | 235/45 R18 | Difference |
|---|---|---|---|
| Overall diameter | 647.1 mm | 668.7 mm | +21.6 mm (+3.34%) |
| Sidewall height | 82.3 mm | 105.8 mm | +23.5 mm |
| Circumference | 2.033 m | 2.101 m | +67.9 mm |
| Revs / km | 491.9 | 476.0 | -15.9 |
| Ground clearance | reference | +10.8 mm | +10.8 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 103.3 km/h | +3.34 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 103.3 km/h after switching to 235/45 R18 — a +3.34% 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 +10.8 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.
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235/35 R19
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235/45 R18
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