Comparison
215/45 R18 vs 235/45 R18
Stepping from 215/45 R18 to 235/45 R18 keeps the 18-inch wheel but widens the section by 20 mm. This sizing approach trims or stretches rolling diameter by a small margin. The wider section adds contact patch and lateral stability, while eating into fender and suspension clearance.
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.
TakeUseful when extra dry grip and stance matter more than a small fuel-economy hit.
Quick math: 235/45 R18 is 18.0 mm taller than 215/45 R18, shifting the speedometer by +2.77%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
+18.0 mm
2.77%
Speedometer at 100
102.8 km/h
+2.77% error
Ground clearance
+9.0 mm
ride height delta
Sidewall change
+9.0 mm
revs/km: 476.0
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/compare/215-45-r18-vs-235-45-r18Detailed comparison
| Metric | 215/45 R18 | 235/45 R18 | Difference |
|---|---|---|---|
| Overall diameter | 650.7 mm | 668.7 mm | +18.0 mm (+2.77%) |
| Sidewall height | 96.8 mm | 105.8 mm | +9.0 mm |
| Circumference | 2.044 m | 2.101 m | +56.5 mm |
| Revs / km | 489.2 | 476.0 | -13.2 |
| Ground clearance | reference | +9.0 mm | +9.0 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 102.8 km/h | +2.77 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 102.8 km/h after switching to 235/45 R18 — a +2.77% 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.
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215/45 R18
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235/45 R18
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