Comparison
225/55 R18 vs 255/45 R18
255/45 R18 is a lower-profile take on 225/55 R18 — same 18-inch wheel, shorter sidewall. This tire combination moves rolling diameter a touch off the original spec. The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. The shorter sidewall gives the tire a firmer, more responsive feel and sharpens steering input. Overall the swap sits inside the safe ±3% diameter window, so ABS, traction control and gearing behave normally.
TakeSuits drivers who value sharper steering and appearance over outright ride softness.
Quick math: 255/45 R18 is 18.0 mm shorter than 225/55 R18, shifting the speedometer by -2.55%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-18.0 mm
-2.55%
Speedometer at 100
97.4 km/h
-2.55% error
Ground clearance
-9.0 mm
ride height delta
Sidewall change
-9.0 mm
revs/km: 463.5
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/compare/225-55-r18-vs-255-45-r18Detailed comparison
| Metric | 225/55 R18 | 255/45 R18 | Difference |
|---|---|---|---|
| Overall diameter | 704.7 mm | 686.7 mm | -18.0 mm (-2.55%) |
| Sidewall height | 123.8 mm | 114.8 mm | -9.0 mm |
| Circumference | 2.214 m | 2.157 m | -56.5 mm |
| Revs / km | 451.7 | 463.5 | +11.8 |
| Ground clearance | reference | -9.0 mm | -9.0 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 97.4 km/h | -2.55 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 255/45 R18 — a -2.55% 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 -9.0 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.
Back to
225/55 R18
Back to
255/45 R18
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