Comparison
225/55 R18 vs 235/55 R17
235/55 R17 drops the rim from 18 to 17 inches versus 225/55 R18, trading wheel size for taller sidewall. This tire combination trims or stretches rolling diameter by a small margin. More tread on the ground tends to improve dry grip and stance, with a small fuel-economy and clearance tradeoff.
Expect a slight but noticeable shift in indicated speed compared to the original tires. Diameter change stays inside the conservative ±3% safety window — an OEM-safe fitment on most vehicles.
TakePractical direction for winter wheels, chains, or rougher pavement where cushioning matters.
Quick math: 235/55 R17 is 14.4 mm shorter than 225/55 R18, shifting the speedometer by -2.04%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-14.4 mm
-2.04%
Speedometer at 100
98.0 km/h
-2.04% error
Ground clearance
-7.2 mm
ride height delta
Sidewall change
+5.5 mm
revs/km: 461.1
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/compare/225-55-r18-vs-235-55-r17Detailed comparison
| Metric | 225/55 R18 | 235/55 R17 | Difference |
|---|---|---|---|
| Overall diameter | 704.7 mm | 690.3 mm | -14.4 mm (-2.04%) |
| Sidewall height | 123.8 mm | 129.3 mm | +5.5 mm |
| Circumference | 2.214 m | 2.169 m | -45.2 mm |
| Revs / km | 451.7 | 461.1 | +9.4 |
| Ground clearance | reference | -7.2 mm | -7.2 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 98.0 km/h | -2.04 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 98.0 km/h after switching to 235/55 R17 — a -2.04% 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 -7.2 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
235/55 R17
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