Comparison
225/55 R18 vs 255/40 R19
255/40 R19 is a plus-1 alternative to 225/55 R18 — the bigger wheel shows through a thinner sidewall. This setup moves rolling diameter a touch off the original spec. The shorter sidewall gives the tire a firmer, more responsive feel and sharpens steering input.
The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeCommon upgrade for sportier handling and a tighter wheel-gap look on the same vehicle.
Quick math: 255/40 R19 is 18.1 mm shorter than 225/55 R18, shifting the speedometer by -2.57%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-18.1 mm
-2.57%
Speedometer at 100
97.4 km/h
-2.57% error
Ground clearance
-9.1 mm
ride height delta
Sidewall change
-21.8 mm
revs/km: 463.6
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/compare/225-55-r18-vs-255-40-r19Detailed comparison
| Metric | 225/55 R18 | 255/40 R19 | Difference |
|---|---|---|---|
| Overall diameter | 704.7 mm | 686.6 mm | -18.1 mm (-2.57%) |
| Sidewall height | 123.8 mm | 102.0 mm | -21.8 mm |
| Circumference | 2.214 m | 2.157 m | -56.9 mm |
| Revs / km | 451.7 | 463.6 | +11.9 |
| Ground clearance | reference | -9.1 mm | -9.1 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 97.4 km/h | -2.57 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 97.4 km/h after switching to 255/40 R19 — a -2.57% 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 -9.1 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
225/55 R18
Back to
255/40 R19
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