Comparison
235/50 R18 vs 275/40 R18
275/40 R18 is a lower-profile take on 235/50 R18 — same 18-inch wheel, shorter sidewall. This swap shifts overall diameter slightly from OEM. The shorter sidewall gives the tire a firmer, more responsive feel and sharpens steering input.
The speedometer offset is small but measurable; worth keeping in mind if you watch the dash closely. 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: 275/40 R18 is 15.0 mm shorter than 235/50 R18, shifting the speedometer by -2.17%.
Current Tire
New Tire
Ground line · scaled comparison
Excellent Fit
Within ±3% — safe for daily driving
Diameter change
-15.0 mm
-2.17%
Speedometer at 100
97.8 km/h
-2.17% error
Ground clearance
-7.5 mm
ride height delta
Sidewall change
-7.5 mm
revs/km: 470.0
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/compare/235-50-r18-vs-275-40-r18Detailed comparison
| Metric | 235/50 R18 | 275/40 R18 | Difference |
|---|---|---|---|
| Overall diameter | 692.2 mm | 677.2 mm | -15.0 mm (-2.17%) |
| Sidewall height | 117.5 mm | 110.0 mm | -7.5 mm |
| Circumference | 2.175 m | 2.127 m | -47.1 mm |
| Revs / km | 459.9 | 470.0 | +10.2 |
| Ground clearance | reference | -7.5 mm | -7.5 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 97.8 km/h | -2.17 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 97.8 km/h after switching to 275/40 R18 — a -2.17% 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 -7.5 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
235/50 R18
Back to
275/40 R18
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