Comparison
235/50 R18 vs 245/40 R19
Switching from 235/50 R18 to 245/40 R19 is a plus-1 upgrade that wraps a shorter sidewall around a larger 19-inch wheel. This setup trims or stretches rolling diameter by a small margin. The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides. Overall the swap sits inside the safe ±3% diameter window, so ABS, traction control and gearing behave normally.
TakeA solid pick for drivers chasing a more aggressive stance without abandoning OEM rolling diameter.
Quick math: 245/40 R19 is 13.6 mm shorter than 235/50 R18, shifting the speedometer by -1.96%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-13.6 mm
-1.96%
Speedometer at 100
98.0 km/h
-1.96% error
Ground clearance
-6.8 mm
ride height delta
Sidewall change
-19.5 mm
revs/km: 469.1
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/compare/235-50-r18-vs-245-40-r19Detailed comparison
| Metric | 235/50 R18 | 245/40 R19 | Difference |
|---|---|---|---|
| Overall diameter | 692.2 mm | 678.6 mm | -13.6 mm (-1.96%) |
| Sidewall height | 117.5 mm | 98.0 mm | -19.5 mm |
| Circumference | 2.175 m | 2.132 m | -42.7 mm |
| Revs / km | 459.9 | 469.1 | +9.2 |
| Ground clearance | reference | -6.8 mm | -6.8 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 98.0 km/h | -1.96 km/h |
Verdict: excellent
Within ±3% — speedometer, ABS and traction control should behave normally.
Speedometer impact
At a true 100 km/h, your dashboard will read 98.0 km/h after switching to 245/40 R19 — a -1.96% 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 -6.8 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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235/50 R18
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245/40 R19
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