Comparison
255/55 R18 vs 235/40 R19
Compared to 255/55 R18, 235/40 R19 is 67.1 mm shorter and changes the speedometer reading by -9.10%.
Current Tire
255/55R18
New Tire
235/40R19
255/55 R18
235/40 R19
Ground line · scaled comparison
Not Recommended
Over 5% — speedometer & ABS may misread
Diameter change
-67.1 mm
-9.10%
Speedometer at 100
90.9 km/h
-9.10% error
Ground clearance
-33.6 mm
ride height delta
Sidewall change
-46.3 mm
revs/km: 474.7
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/compare/255-55-r18-vs-235-40-r19Detailed comparison
| Metric | 255/55 R18 | 235/40 R19 | Difference |
|---|---|---|---|
| Overall diameter | 737.7 mm | 670.6 mm | -67.1 mm (-9.10%) |
| Sidewall height | 140.3 mm | 94.0 mm | -46.3 mm |
| Circumference | 2.318 m | 2.107 m | -210.8 mm |
| Revs / km | 431.5 | 474.7 | +43.2 |
| Ground clearance | reference | -33.6 mm | -33.6 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 90.9 km/h | -9.10 km/h |
Verdict: danger
Over 5% diameter difference — likely to affect speedometer accuracy, ABS calibration and gearing. Not recommended without professional review.
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255/55 R18
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235/40 R19