Comparison
245/60 R18 vs 255/55 R18
Stepping from 245/60 R18 to 255/55 R18 keeps the 18-inch wheel but widens the section by 10 mm. This alternative fitment moves rolling diameter a touch off the original spec.
Expect a slight but noticeable shift in indicated speed compared to the original tires. The shorter sidewall gives the tire a firmer, more responsive feel and sharpens steering input. The wider section adds contact patch and lateral stability, while eating into fender and suspension clearance. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakeReasonable performance-leaning swap as long as fender and suspension clearance check out.
Quick math: 255/55 R18 is 13.5 mm shorter than 245/60 R18, shifting the speedometer by -1.80%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-13.5 mm
-1.80%
Speedometer at 100
98.2 km/h
-1.80% error
Ground clearance
-6.8 mm
ride height delta
Sidewall change
-6.8 mm
revs/km: 431.5
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/compare/245-60-r18-vs-255-55-r18Detailed comparison
| Metric | 245/60 R18 | 255/55 R18 | Difference |
|---|---|---|---|
| Overall diameter | 751.2 mm | 737.7 mm | -13.5 mm (-1.80%) |
| Sidewall height | 147.0 mm | 140.3 mm | -6.8 mm |
| Circumference | 2.360 m | 2.318 m | -42.4 mm |
| Revs / km | 423.7 | 431.5 | +7.8 |
| Ground clearance | reference | -6.8 mm | -6.8 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 98.2 km/h | -1.80 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 98.2 km/h after switching to 255/55 R18 — a -1.80% 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 -6.8 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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245/60 R18
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255/55 R18
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