Comparison
255/55 R18 vs 275/40 R19
Plus-sizing from 255/55 R18 to 275/40 R19 keeps overall diameter close to factory while opening room for a larger 19-inch wheel. This setup swings rolling diameter far enough to feel on the road. The speedometer error is noticeable and may warrant a recalibration if you rely on indicated speed. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides. Diameter delta falls in the cautious 3–5% range, where speedometer recalibration and a careful clearance check are worth doing.
TakeA solid pick for drivers chasing a more aggressive stance without abandoning OEM rolling diameter.
Quick math: 275/40 R19 is 35.1 mm shorter than 255/55 R18, shifting the speedometer by -4.76%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
-35.1 mm
-4.76%
Speedometer at 100
95.2 km/h
-4.76% error
Ground clearance
-17.6 mm
ride height delta
Sidewall change
-30.3 mm
revs/km: 453.0
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/compare/255-55-r18-vs-275-40-r19Detailed comparison
| Metric | 255/55 R18 | 275/40 R19 | Difference |
|---|---|---|---|
| Overall diameter | 737.7 mm | 702.6 mm | -35.1 mm (-4.76%) |
| Sidewall height | 140.3 mm | 110.0 mm | -30.3 mm |
| Circumference | 2.318 m | 2.207 m | -110.3 mm |
| Revs / km | 431.5 | 453.0 | +21.6 |
| Ground clearance | reference | -17.6 mm | -17.6 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 95.2 km/h | -4.76 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 95.2 km/h after switching to 275/40 R19 — a -4.76% 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 -17.6 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
255/55 R18
Back to
275/40 R19
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