Comparison
225/40 R19 vs 255/35 R18
Minus-sizing from 225/40 R19 to 255/35 R18 pairs a smaller 18-inch wheel with more rubber between the rim and road. This sizing approach noticeably changes overall diameter compared to OEM. Indicated speed will drift far enough that recalibration is worth considering. Expect a more planted steering feel, at the cost of some of the cushioning a taller sidewall provides. Diameter delta falls in the cautious 3–5% range, where speedometer recalibration and a careful clearance check are worth doing.
TakeTypical choice for a dedicated winter or off-road setup where extra sidewall pays off.
Quick math: 255/35 R18 is 26.9 mm shorter than 225/40 R19, shifting the speedometer by -4.06%.
Current Tire
New Tire
Ground line · scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
-26.9 mm
-4.06%
Speedometer at 100
95.9 km/h
-4.06% error
Ground clearance
-13.4 mm
ride height delta
Sidewall change
-0.8 mm
revs/km: 500.7
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/compare/225-40-r19-vs-255-35-r18Detailed comparison
| Metric | 225/40 R19 | 255/35 R18 | Difference |
|---|---|---|---|
| Overall diameter | 662.6 mm | 635.7 mm | -26.9 mm (-4.06%) |
| Sidewall height | 90.0 mm | 89.3 mm | -0.8 mm |
| Circumference | 2.082 m | 1.997 m | -84.5 mm |
| Revs / km | 480.4 | 500.7 | +20.3 |
| Ground clearance | reference | -13.4 mm | -13.4 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 95.9 km/h | -4.06 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 95.9 km/h after switching to 255/35 R18 — a -4.06% 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 -13.4 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
225/40 R19
Back to
255/35 R18
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