Comparison
235/45 R18 vs 245/45 R19
245/45 R19 is a plus-1 alternative to 235/45 R18 — the bigger wheel shows through a thinner sidewall. This setup noticeably changes overall diameter compared to OEM. The dashboard speed will be significantly off — plan on recalibration before daily use. More tread on the ground tends to improve dry grip and stance, with a small fuel-economy and clearance tradeoff. The diameter gap exceeds 5%, which can affect speedometer accuracy, ABS calibration and final gearing — review with a professional first.
TakeRecommended only after a professional fitment check and speedometer recalibration.
Quick math: 245/45 R19 is 34.4 mm taller than 235/45 R18, shifting the speedometer by +5.14%.
Current Tire
New Tire
Ground line · scaled comparison
Not Recommended
Over 5% — speedometer & ABS may misread
Diameter change
+34.4 mm
5.14%
Speedometer at 100
105.1 km/h
+5.14% error
Ground clearance
+17.2 mm
ride height delta
Sidewall change
+4.5 mm
revs/km: 452.7
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/compare/235-45-r18-vs-245-45-r19Detailed comparison
| Metric | 235/45 R18 | 245/45 R19 | Difference |
|---|---|---|---|
| Overall diameter | 668.7 mm | 703.1 mm | +34.4 mm (+5.14%) |
| Sidewall height | 105.8 mm | 110.3 mm | +4.5 mm |
| Circumference | 2.101 m | 2.209 m | +108.1 mm |
| Revs / km | 476.0 | 452.7 | -23.3 |
| Ground clearance | reference | +17.2 mm | +17.2 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 105.1 km/h | +5.14 km/h |
Verdict: danger
Over 5% diameter difference — likely to affect speedometer accuracy, ABS calibration and gearing. Not recommended without professional review.
Speedometer impact
At a true 100 km/h, your dashboard will read 105.1 km/h after switching to 245/45 R19 — a +5.14% 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 +17.2 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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235/45 R18
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245/45 R19
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