Comparison
225/60 R17 vs 255/55 R18
255/55 R18 is a plus-1 alternative to 225/60 R17 — the bigger wheel shows through a thinner sidewall. This sizing approach noticeably changes overall diameter compared to OEM. The shorter sidewall gives the tire a firmer, more responsive feel and sharpens steering input.
The dashboard speed will be significantly off — plan on recalibration before daily use. 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: 255/55 R18 is 35.9 mm taller than 225/60 R17, shifting the speedometer by +5.12%.
Current Tire
New Tire
Ground line · scaled comparison
Not Recommended
Over 5% — speedometer & ABS may misread
Diameter change
+35.9 mm
5.12%
Speedometer at 100
105.1 km/h
+5.12% error
Ground clearance
+18.0 mm
ride height delta
Sidewall change
+5.3 mm
revs/km: 431.5
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/compare/225-60-r17-vs-255-55-r18Detailed comparison
| Metric | 225/60 R17 | 255/55 R18 | Difference |
|---|---|---|---|
| Overall diameter | 701.8 mm | 737.7 mm | +35.9 mm (+5.12%) |
| Sidewall height | 135.0 mm | 140.3 mm | +5.3 mm |
| Circumference | 2.205 m | 2.318 m | +112.8 mm |
| Revs / km | 453.6 | 431.5 | -22.1 |
| Ground clearance | reference | +18.0 mm | +18.0 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 105.1 km/h | +5.12 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 255/55 R18 — a +5.12% 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 +18.0 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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225/60 R17
Back to
255/55 R18
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