Comparison
225/55 R18 vs 245/45 R18
245/45 R18 is a lower-profile take on 225/55 R18 — same 18-inch wheel, shorter sidewall. This alternative fitment moves rolling diameter well outside the usual OEM tolerance. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides.
Indicated speed will drift far enough that recalibration is worth considering. Diameter delta falls in the cautious 3–5% range, where speedometer recalibration and a careful clearance check are worth doing.
TakeSuits drivers who value sharper steering and appearance over outright ride softness.
Quick math: 245/45 R18 is 27.0 mm shorter than 225/55 R18, shifting the speedometer by -3.83%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
-27.0 mm
-3.83%
Speedometer at 100
96.2 km/h
-3.83% error
Ground clearance
-13.5 mm
ride height delta
Sidewall change
-13.5 mm
revs/km: 469.7
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/compare/225-55-r18-vs-245-45-r18Detailed comparison
| Metric | 225/55 R18 | 245/45 R18 | Difference |
|---|---|---|---|
| Overall diameter | 704.7 mm | 677.7 mm | -27.0 mm (-3.83%) |
| Sidewall height | 123.8 mm | 110.3 mm | -13.5 mm |
| Circumference | 2.214 m | 2.129 m | -84.8 mm |
| Revs / km | 451.7 | 469.7 | +18.0 |
| Ground clearance | reference | -13.5 mm | -13.5 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 96.2 km/h | -3.83 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 96.2 km/h after switching to 245/45 R18 — a -3.83% 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 -13.5 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
245/45 R18
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